We have a 2015 and a 2017. The 2015 is an all-wheel-drive. Both make that rumbling sound as if you’re starting off in second gear on a manual transmission car. The dealer says it’s normal with this CVT transmission. I find it annoying, But have had no issues. There was a clunk in the 2015 AWD and brought it back to the dealership and they took care of it at no charge. I bought the 2017 in 2019 and the 2015 I bought in 2020. Both have lifetime guarantee on the drivetrain and I took out a separate warranty on the electronics.

 

For reference from my PCV valve replacement thread...

https://www.nissanmurano.org/threads/2021-awd-pcv-valve-replacement-at-84-000-miles.228316/post-783611

So the rumble has persisted since my post about it first happening around October 2023, roughly 28 months after buying this vehicle new. Today, though, after running some errands and starting the car several times over a seven-hour period, the last time I started it the RPMs shot very high (maybe even above 4,500) and then slowly wandered down to normal. FYI, I never touched the gas pedal when starting the engine, and I never have since owning this car.

Once on my way, the car was driving smoother and without the rumble noise and vibration, and the RPMs at cruise control speeds were where they used to be, and acceleration was peppy and responsive again and didn't seem to drag. Will have to see if the rumble is still gone in the morning. MPG over the past Winter months has been 23.5, and is currently 23.9.

Since owning this vehicle I've had a few odd things happen which I felt were related to a vacuum deficiency due to a slow recovery under certain braking, accelerating or fast steering scenarios (or combinations of those things). I'm leaning towards something being wrong with the vacuum booster or a hose connected to it. I'll have to explore this idea at some point to see if I can manipulate what's happening.

 

Next morning of getting gas, stops and starts, and the rumble-vibration is still gone. The ride really is far more enjoyable with those elements absent. Even general braking seems smoother.

Also BTW, I had done nothing to the car for service in the weeks leading up to the rumble issue vanishing. I'm going to try to avoid hard acceleration and braking in an effort to keep the rumble away

Another thread about the noise and vibration...

https://www.nissanmurano.org/threads/low-rpm-vibration-noise.188138/post-522978

 

To update, the rumble is still gone. The only thing I did around the time the rumble went away was to use a leaf blower to blow out the engine bay of dust and whatnot. Happy the sound is gone, but no idea why it's gone.

 

The rumble is still gone, though I swear it returned for a few hours during a rainstorm a few weeks ago. Still no clue why it vanished. I've been trying to force it to return with no luck.

 

Rumble is still gone. MPG over the past two months has been a solid 25.9, and that's with the crazy heatwave and using A/C a lot. That's in contrast to 23.9 during winter months with the rumble present. The lowest MPG I got over the winter for about three weeks was 22.1.

Currently at 99,000+ miles, I'm looking forward to replacing the spark plugs within the next month, as well as doing an extensive service on the CVT.

 

Rumble is still gone. MPG over the past two months has been a solid 25.9, and that's with the crazy heatwave and using A/C a lot. That's in contrast to 23.9 during winter months with the rumble present. The lowest MPG I got over the winter for about three weeks was 22.1.

Currently at 99,000+ miles, I'm looking forward to replacing the spark plugs within the next month, as well as doing an extensive service on the CVT.

Is the rumble still gone at this point I just ordered a new PVC valve hoping it will solve my issue thanks for any reply 21 sv with 81k miles here done it since I bought it with 57k has grown very annoying the more I drive it

 

Rumble is still gone and MPG has been a steady 26.7. Keep in mind that the rumble eventually returned for roughly six months after replacing the PCV valve, so I don't consider it to be a fix for the rumble. @MuranoSL2003 has had the rumble since his car was new, and he bought a PCV valve to see if that would get rid of the rumble. I don't think he posted to update, which leads me to believe it didn't help.

My thoughts are still that something related to the vacuum system is deficient. Stopping and revving the engine quickly above 4000 RPM eliminated the rumble after the PCV valve was changed and the rumble stopped and then returned, but after doing that two or three more times I just kind of lived with it. In April 2024 it went away and has remained gone.

Revving the engine to 4000 RPMs might generate more vacuum to make everything work correctly, but over time something happens and vacuum is again limited or restricted by something and the rumble returns. Or, maybe the high rev does something to part of the air delivery system or the throttle body controller.

 

I appreciate the information. I will be changing my pcv valve tomorrow since my 21 is right at 81k now just for piece of mind , I will try the revving the rpms to 4000 a few times and see what happens and keep my fingers crossed. I am hoping to keep my Murano for around 6 more years as a daily driver before I retire it to a work car but that rumble drives me nuts and it doesn't happen all the time shows up at random.

 

I appreciate the information. I will be changing my pcv valve tomorrow since my 21 is right at 81k now just for piece of mind , I will try the revving the rpms to 4000 a few times and see what happens and keep my fingers crossed. I am hoping to keep my Murano for around 6 more years as a daily driver before I retire it to a work car but that rumble drives me nuts and it doesn't happen all the time shows up at random.

I appreciate the information. I will be changing my pcv valve tomorrow since my 21 is right at 81k now just for piece of mind , I will try the revving the rpms to 4000 a few times and see what happens and keep my fingers crossed. I am hoping to keep my Murano for around 6 more years as a daily driver before I retire it to a work car but that rumble drives me nuts and it doesn't happen all the time shows up at random.

Update : I changed out the PVC valve everything is noticably better but the rumble still shows up. I did the revving thing to see if it would help it did , but would shortly return after around 10 mins I'll keep running it only time will tell but to get more a response out of it was worth it and needed done anyways.

 

I believe I had pulled over, restarted the engine, left it in P and then goosed the gas pedal quickly and enough to have it hit a little above 4000 RPMs. Your rumble returned fairly quickly. What octane fuel do you use? I don't think it matters, but it doesn't hurt to find out, in case all the pieces come together later to point to octane as a factor in possibly clogging or sooting up something.

 

I had been just running regular 87 I have since switched to 93 octane just got done running 3 bottles of cleaner through it so I could do a severe clean since it probably has never been done in its life. I have also recently changed cvt fluid did it at 60k and 70k just to get most of the oil fluid out of the system. I just want to resolve this issue and maybe help others resolve it , I also changed out the exhaust hanger piece more towards the cvt read a thread that those wear out quickly. Next step will be spark plugs may change serpentine belt and tensioner pulley just as maintenance could very well solve the issue that way but idk lol.

 

Yeah I have that. Because the CVT control deliberately lugs the transmission at high load and low RPM. I don't think there's any fixing that as we can't change that goofy control behavior. I rented a brand new Altima a while back and they don't do that any more I suspect because they know nobody likes feeling/noises of the engine lugging off the absolute bottom of the RPM range when you put your foot down.

 

Very interesting that the vibration stayed gone for months then randomly showed back up after that. I will be taking a look at mine and maybe see if the oring can be replaced. Thanks for the tip 😁

 

Here's something interesting (and dumb)... I had the rumble-vibration suddenly begin this morning at 1000 RPMs. After returning home I was under the hood to check on some fuses to help someone here when I noticed the CVT fill-tube pressure cap was resting on the plastic radiator cover. I had removed it the previous night while trying out a new endoscope and forgot about it. I just put it back on but haven't driven yet. Curious to see if that has any effect.

What's important to keep in mind is, around the time the rumble began for me for the first time last year I had replaced the CVT fluid a month or so prior. Is it possible there's a design flaw with some of those pressure caps where if they aren't seated correctly into the tube air will be drawn into the CVT and cause the rumble and vibration to occur? Maybe if you're lucky, over time the O-ring will seal correctly and the problem goes away (such as when it happened to me last year once the cold temperatures passed - the rumble went away). With others, maybe their cap was damaged from the start (such as in @MuranoSL2003's case) and maybe trying a new cap or maybe rubbing some petroleum jelly around the O-ring might make it seal correctly and get rid of the rumble. I also just remembered that I had ordered a spare pressure cap and had tried the cap out sometime between changing the fluid and the rumble starting. Maybe when I put the original cap back on it was dry and it moved around and then air started getting sucked in. And I sometimes fool around with the pressure cap when wiping down the engine, so maybe something I did at some point last April helped it to seal differently. Also something to keep in mind is how your car is stored. Mine is always in a semi-heated garage, so even during the Winter things never freeze. If the O-ring is the problem and you park your car outside during the Winter, maybe that coldness would cause a poorly seated O-ring not to be able to rebound back to its shape, and over the course of an entire cold season, just maybe a damaged O-ring would hold that flat spot permanently, meaning the rumble would never go away. In that scenario, I'm thinking about @MuranoSL2003's car.

Maybe the act of revving to 4000RPM helps it go away for a brief time under certain conditions by sudden fluid pressure nudging the o-ring so it sits a bit differently to fill a void or something. I think a simple test would be to remove the pressure cap and rub a little Marvel Mystery Oil or tranny/CVT fluid around the O-ring (maybe even remove the O-ring to lubricate it everywhere) then while inserting the cap shimmy-twist it a little before it locks into place. Maybe turn the cap 180 out and twist-push it down further than it needs to go in order to lube the inside of the tube. It's possible the pressure cap may have been pried out or left somewhere where something compressed a tiny portion of the O-ring and a flat spot was created.

I'll update this post once I've gone for a drive...

Just in case someone needs it, the part # for the pressure cap is 31086-3TA1A. Here are some comparison photos of new & old.

 

Here's something interesting (and dumb)... I had the rumble-vibration this morning. Out of the blue. After returning home I was under the hood to check on some fuses to help someone here when I noticed the CVT fill-tube pressure cap was resting on the plastic radiator cover. I had removed it the previous night while trying out a new endoscope and got sidetracked watching the footage and scoping other things that I forgot all about it...

I just put it back on but haven't driven it again yet. Curious to see if that has any effect.

Now, what's important to keep in mind is, around the time the rumble began for me, I had replaced the CVT fluid a month or so prior. Is it possible there's a design flaw with some of those pressure caps where if they aren't seating correctly into the tube, it will allow air to be drawn in and cause the rumble and vibration to occur. Maybe if you're lucky, over time the o-ring will seal correctly and things go away (such as when it happened to me last year once the cold temperatures passed). With others, maybe their cap was damaged from the start (such as in @MuranoSL2003's case) and maybe trying a new cap or maybe rubbing some petroleum jelly around the O-ring might make it seal things and get rid of the rumble. Maybe the act of revving to 4000RPM helps it go away for a brief time under certain conditions.

I'm at work for the next 40 hrs or so if you happen to drive yours after reseating yours and it solves the issue again letting us know it would be greatly appreciated 👍

 

After a quick 60MPH drive to/from the store, the rumble is still there but the vibration not so much.

Before leaving the store I decided to start the car, pull the pressure cap, replace the cap, hit the gas pedal to rev to 4000 and get underway. It only revved to 3500 and so I just drove away. Responsiveness and smoothness were fine, but the rumble was still there. BTW, when I pulled the cap with the engine running, I placed a thumb over the tube opening and the engine did idle ever-so-slightly differently (a hint louder with no thumb-blocking) and there did seem to feel like a bit of suction on my thumb.

I usually check MPG and tire pressure twice a day (first/last drives) and MPG had been solid at 26.7 for about the past two months (including yesterday). It's now showing 26.1. This seems like a repeat of what happened last year, where MPG tanked to 25.x once the rumble started.

The outside temps have been consistently more cold today than any other so far this Fall, so maybe that has something to do with it. I might use the new pressure cap tomorrow morning to see if anything different happens. It's entirely possible that after driving 150+ miles today with the cap off that things sounded/felt differently than they normally would when the cap's on and the rumble is present. The "cap off" condition may have made the drive more extreme to now make the normal rumble-vibration seem less intense.

 

Interesting 🤔 I went ahead my intrusive thoughts got the best of me and I went by my house and threw on a new 0 ring a little thicker than what was on it and it made a better seal. I did not get to drive it though since I drive a company vehicle so i won't get to until Monday around 9am I'm hoping for better results. Keep us updated on what your findings are you have been very helpful in narrowing this issue down and it's greatly appreciated 👍

 

I didn't use the new cap this morning and I didn't even touch anything. After getting gas I did do the rev thing, but it didn't seem to work as well as it did last time. Acceleration was a little smoother at first, but then everything returned within maybe 20 minutes.

I'd forgotten how much differently that car feels/drives with the rumble-vibration present. The smoothness at lower speeds to 40MPH is lacking. The problem is that the rumble starts right at 1MPH as you depress the gas pedal lightly. You kind of have to push through that murkiness to get the car sounding and feeling more normal, but that's only if the RPMs are forced above 1100. The car drives smoother when first cold than once warmed up, but only with regard to the rumble-vibration. The CVT itself does not feel smooth when the CVT fluid is still cold. The variations are bit jarring.

What's odd is that things are seeming nearly identical to how things transpired last year. Around Aug 2023 I'd changed the CVT fluid, everything was great, and then two months later the rumble started. Flash ahead to Aug 2024, I changed the CVT fluid (decided against doing the internal metal filter), everything was great, and then now in November the rumble has started.

The only common denominators leading up to the rumble appearing are the CVT fluid being changed and cold Autumn temperatures. But in between those two events the car was running smooth to super-smooth (after the new RuthHX plugs).

 

I had actually changed the internal metal filter and the external paper filter on the side of the cvt and my rumble went away for about 30 mins then returned. My 21 drives very smooth don't even feel the simulation shifts I guess that's what you would call them unless I punch the throttle. I have noticed on take off sometimes it holds back before going on like a slight hesition but that's only on take off but if I punch it getting on the road then it never hesitates a bit. I will let you know if mine changes any on Monday when I get to drive it , I did put a bigger O ring on that fit snug and sealed tightly down into the fill tube fingers crossed 🤞 supposed to be around 67° here tomarrow in Kentucky.

 

I had actually changed the internal metal filter and the external paper filter on the side of the cvt and my rumble went away for about 30 mins then returned.

I was thinking of buying a second inspection filter cover/housing to try to create something magnetic around it to help capture more metal particles. I was thinking I could bore a hole in the top and either thread the hole or use epoxy to affix a clear cylinder that would allow flowing fluid to enter passively and catch metal that would be easier to see. Not sure there's enough room for that, though. For my 2003, I'd always wanted to make some kind of inline magnetic filter thing that had a clear casing that I could easily inspect to see if metal is in the system, and make it easy to change the filter. Never did it. So far with this 2021 I haven't found any metal in the drained fluid, on test swabs from deep within the pan, or on the paper filter. Combined with the car running so well at 100,000 miles, I decided not to tamper with a perfectly good pan seal. Maybe at 150,000 miles...

Unfortunately, the scoping wasn't a success because once at the entrance to the pan there was resistance, and I was worried if I went in too far the head of the scope would snag on the metal edge when trying to pull it back out, which would force me to have to drop the pan to correct the problem. I pushed it in about halfway once, but then it was tough to remove. Since the space is so tight with bends along the way, trying to manipulate the scope in the direction I wanted to look would have been impossible anyway, so... Basically I'd end up seeing whatever was at the very bottom of the pan below the fill tube - or at whatever the scope just happened to be facing. I think it should be the pan magnets, but there was a pipe end (which I think is the fluid return) that the scope's LEDs kept glaring off of and making it impossible to see the bottom of the pan. I had tried to scope via the pan's drain plug hole and overfill hole with my other scope, but that was pointless because it was too rigid and the spaces to tight to achieve the desired viewing angles. I need to modify the base/rear of this other scope's lens casing so it's smooth and can't get hung up on anything when being retracted. And the lens casing may only be held onto the main wire harness by friction, so I don't want the head popping off and turning sideways and becoming hopelessly stuck down there.

Not exactly Fantastic Voyage...

 

I have even tried raising the rpms by 250 bc that's the max I can raise them with the cvtz50 app. it still falls down to that 1000 rpm regardless of having the rpms raised.the app is a useful tool for checking engine and cvt code fluid deterioration numbers idle relearns etc.

 

I think the app's RPM adjustment affects the idle and nothing more - at least that's all it did when I used it on my 2003 AWD. It won't have any bearing on the driving engine until acceleration has ended and the engine is allowed to return to idle speed.

 

I was going to express concern about using a bigger O-ring, but then I was thinking any pressure venting would probably happen through the center of the pressure cap since the cap is locked in place and couldn't just pop off if pressure was too great. I'll have to look more closely at how that cap looks/works.

The first time I scoped the tube I saw a set of side holes further in (probably already into the CVT casing) and thought they may exist to divert excess CVT fluid and possibly expel air, possibly through the CVT casing's breather hose/tube (for the air, not for excess fluid).

 

I was going to express concern about using a bigger O-ring, but then I was thinking any pressure venting would probably happen through the center of the pressure cap since the cap is locked in place and couldn't just pop off if pressure was too great. I'll have to look more closely at how that cap looks/works.

When I scoped the fill tube the other night, I noticed two sets of side holes at different depths within the tube (probably already into the CVT casing) and thought they may exist to divert excess CVT fluid and possibly air to get rid of it...possibly through the CVT casing breather hose/tube (for the air, not any excess fluid).

View attachment 59304

That's cool to see down inside the filler tube. First time I've seen into it I'm learning more and more about these muranos I am in a Facebook group and tons and tons of people are having the rumbling noise and no fix in sight. This is the closest I've came to any type of solution on fixing it lol so I'll keep trying things til eventually something works or I trade it in.

 

I noticed today that while in P with the engine running and warmed up, if I tapped/released the gas pedal maybe 1/4" the RPMs went to about 2200, held for a few seconds and then halfheartedly wandered down to idle. Typically when I've done that the tach needle hits the RPM range and quickly snaps back to idle. Pushing the pedal about halfway had a more normal engine sound and tach needle movement, but it's still not normal. And to be clear, the engine is caught "racing" during that RPM wandering, it's not simply the needle acting funny.

I remember posting about RPM tach needle wandering about 1.5-2 years ago, that was also accompanied by a ghostly sound that one morning. I'll have to revisit that post to see what I wrote. Perhaps that was the first indication of the rumble coming to life.

 

Update to mine this morning drove it about 45 mins I did notice the rumble got a lot quieter compared to before with the larger o ring in place

 

So things have changed to where now the rumble-vibration is happening from 1000-1250 RPM, even with cruise control engaged. The only time the rumble is gone is when the car accelerates even a hair. The split second the engine locks into a steady speed the rumble returns. The only exception is when driving down a slope where light engine braking increases the RPMs.

The crappy part is that it's now even more noticeable at slower speeds, so if from a stopped position I accelerate normally with traffic using a steady, light pedal depression the rumble is persistent because it's now happening within a wider RPM range. To kill the rumble, I'd have to keep goosing the pedal and surging towards the vehicle ahead of me.

I might pull the PCV valve and try the new cap, but from what others are indicating it's not really a lasting solution - if it even helps at all. I might toss a recording a device under the car and drive around to see if anything can be picked up.

 

Driving mine this morning 32° weather the rumble was much more noticable and stayed present more. Yesterday 64° weather the rumble was almost gone or hardly noticable at all in fact it was harder to even get it to rumble at all I was happy as could be just for it to be terrible again this morning. Cold temps defently play a role from what I can tell no issues so far with that bigger O ring installed but it also didn't remedy it either and new pcv valve doesn't have 200 miles on it yet.

 

Something I noticed but had forgotten about that might be valuable in order to figure this out: When the rumble is happening, the instant the gas pedal is released a hair or fully, the rumble is gone (even when the RPMs are still within the rumble range). Same applies to using cruise. As soon as cruise is turned off or disengaged the rumble goes away instantly.

Obviously, when the car is accelerating there are more mechanical components being strained/pressed against each other (that might create more friction or vibration) than when coasting along with those parts more passively engaging one another. But, when on a level road at slow speed where there's not as much stress/force at work, barely letting off on the gas pedal makes the rumble stop instantly, and barely pressing the gas pedal instantly makes the rumble start again.

Given the gentleness of the drive when the rumble can be manipulated with a hair-trigger touch, I almost think the issue isn't with the CVT, but with the throttle body. The gas pedal is electronically controlled, so something is reacting very rapidly to the gas pedal movement to force the rumble. I don't think it's possible for the CVT to react so quickly to such a delicate event.

I don't think the TPS (throttle position sensor) is the problem because the engine idles smoothly and drives fine aside from the rumble.

Thinking about what @vovexe said in the 1st Gen forum about the CVT having some kind of adaptive learning ability to account/compensate for some degree of wear, I wonder if there's a learning algorithm at play somewhere in the system that's sometimes confused about what's actually happening, and it's providing inaccurate information to other systems (and maybe those incorrect values are somehow being retained until something happens to change them to normal) which is causing something to act abnormally. Maybe the rumble and vibration are coming from the air delivery system and it's making the engine shake a little.

Or, maybe the motor mounts are adjusting the wrong amount when the gas pedal is touched, which is creating more stresses on moving parts as the pitch of the engine and drivetrain change. I believe the mounts may only soften or stiffen, so I'm not sure if it's possible those simple changes could produce such a dramatic event. I don't know how the motor mounts interact with other systems (if at all), but I was thinking if pressing the gas pedal would automatically cause the engine to change its orientation within the engine bay (to any degree) then I would link the electronics would be programmed to tell the motor mounts when the gas pedal is pressed and released (and by how much each way) so it can adjust to the anticipated changes in orientation as torque increases.

My "theory" being if values are sometimes being set wrong and telling the motor mounts to soften when they should stiffen, maybe that could throw things off enough to produce the rumble. I do a lot of fast braking to pull over for idiots who tailgate. Maybe those dramatic events sometimes get the system confused as to what's happening, and the wrong values are set. Maybe doing a certain crazy braking maneuver would set the values straight again. Maybe that's why the rumble went away for such a long time. And until about a month ago I was trying to show more control (alright...maturity) by being less aggressive in my fast-braking into the breakdown lane. But recently there were times when there was nowhere to pull over safely, and when I finally saw a place I'd quickly put on my directional or hazards and brake quickly into the safe zone. So, at least in my case, those extreme braking events are something I need to consider. If all of you with the rumble don't perform such dramatic brake/steering maneuvers, I guess my braking events aren't the cause of the rumble or of values being set wrong.

I think it might be interesting to accelerate and brake at the same time to see what happens while the rumble is going on. It might be worthwhile to pull the fuse or relay to the motor mounts so they can't do anything while driving to see if the rumble is gone or changes its behavior.

 

This is a great video about the Nissan Murano hydraulic motor mount and how it works. I've cued it up to where the guy stops ranting about what he's going to do... In short, the mounts are soft when engine RPMs are under 1000, and they stiffen when exceeding 1000, so on the surface there could be something here that pertains to the rumble. I haven't located the fuse/relay yet, so I might just pull one electrical connector at a time to each mount and then take a test drive. I still don't know if the interaction of the motor mounts goes beyond a simple programming of knowing and responding to an under/over 1000 RPM parameter. Perhaps an under-voltage is causing the mounts to adjust poorly. Hey...I remember that mystery Bridgestone module... @I need coffee

 

Weather or not the function actually works or not their is an option to move the motor mounts via the cvtz50 app. I'll try it out and see what happens.

 

Thinking about what @vovexe said in the 1st Gen forum about the CVT having some kind of adaptive learning ability to account/compensate for some degree of wear, I wonder if there's a learning algorithm at play somewhere in the system

CVT learnings can be cleared by erasing TCM memory (after which it will be necessary to write calibration data and to perform "clutch point learning" procedure).
"clutch point learning" by the way... Maybe results of this learning also influencing what's happening at 1000rpm.

Engine learnings also resettable and this is easier - no need to do anything afterwards.

that's sometimes confused about what's actually happening, and it's providing inaccurate information to other systems (and maybe those incorrect values are somehow being retained until something happens to change them to normal)

Engine for example continuously broadcasts current estimated torque lbft it produces and CVT somehow uses these numbers. So if real torque is noticeably different from the expected value then CVT can go rough.

 

CVT learnings can be cleared by erasing TCM memory (after which it will be necessary to write calibration data and to perform "clutch point learning" procedure).
"clutch point learning" by the way... Maybe results of this learning also influencing what's happening at 1000rpm.

Engine learnings also resettable and this is easier - no need to do anything afterwards.


Engine for example continuously broadcasts current estimated torque lbft it produces and CVT somehow uses these numbers. So if real torque is noticeably different from the expected value then CVT can go rough.

Thanks for the insight. I was actually thinking about some system other than the CVT that may have some learning process that's trying to adjust things somewhere, and is setting values/parameters that don't actually make sense, or that make sense in the moment but later aren't cleared and brought back to normal. I don't know if the CVT is that hyper-sensitively influenced by a minor pedal release/depression. Particularly on the pedal release which feels like a nudge let-up and isn't an extreme act. I can't imagine the CVT would produce such a rumble and then it's gone in a fraction of a second by an almost non-event event. Then, again, we are talking about an electronics system, so things will react instantly as opposed to a cable-driven pedal which will likely have some fractional time delay when compared to electrical signals communicating something.

 

Rumble was present this morning, only quieter. Oddly, rumble was not there while using cruise. Gas pedal response was actually good. Later in the morning after shopping for about about 15 minutes, I fired up MO and there was a "swarm of insects" sound coming from what seemed to be the driver's side area beneath the hood. It was noticeable prior to shifting from P to D, and still noticeable after shifting to D and starting forward. Nothing made it change its frequency or go away. This was not the same "chainsaw" or "swarm of bees" noise I originally posted about last year.

Went into a place for about an hour, came back out and started the car and that insect noise wasn't there. Maybe noise from the master cylinder? Rumble and conditions were still the same as earlier in that morning, but the vibration aspect of the rumble problem did not seem obvious.

 

Update: I tried the braking thing you were talking about and my rumble is gone. I ran it up to 70 and braked down to 20 and took off again then when slowing down for a light I did some aggressive braking just for extra assurance I will update when it returns. Seems to be a temporary fix at least or could even be a permanent fix but I'm not holding my breath 😆

 

My rumble is basically the same as yesterday: a bit quieter with less vibration and good pedal response.

It's never been a permanent fix for me; lasts a handful of days, if that. But at the very least it does seem to quiet the rumble and the vibration by maybe 70% (when it's not eliminated completely by doing that) so something happening during high-RPM events (or fast braking, accelerating) is affecting something that's making things change.

Just another piece of the jigsaw. I think we have too many similar edge pieces at the moment to conclude much of anything.

I think my new line of thinking is going to be the IPDM and surrounding relays/fuses in various boxes. I noticed there are a couple of capacitors in that area, and was thinking maybe something's not discharging correctly, or maybe an applicable relay is hyper-clicking and causing the swarm of insects noise. While that insect noise and rumble don't appear to be connected, you never know. BTW, the insect noise hasn't returned.