noise upon/slow acceleration

[Linds]

So I've been searching and searching this forum and others trying to figure out what is wrong with my car, to no avail.

Here's the rundown:

04 SL
99000 mi

noise upon acceleration - a rattling sound...I found a supermarket bonus card in one of the inside air vents thinking that was the problem, but it was removed and still does it...sound is not present at idle, nor can you hear it when the car is in park and the engine is revved...sound is slight upon slight acceleration and gets louder as you accelerate harder

slow acceleration - feels bogged down...very difficult to accelerate at highway speeds, for instance, cruising at 50mph, hitting the gas moderately causes the rpms to move up and drop back down with very little if any gain in speed, it can also be difficult to get up hills...there is no surging or stalling

other - a bit of a rough idle...upon acceleration, engine sounds louder than normal, even from cabin with windows closed, not a sound i can describe as being like something else, just that it sounds like the engine is working too hard

Also thank you if you're still reading!

What I have tried:
I have replaced the spark plugs and the throttle body, cleaned the MAF sensor, used fuel injector cleaners in my gas, done an oil change...nothing has made a bit of difference. I've tried different gasolines, and while the problems do seem to be compounded by regular gas versus premium, the problems do not at all go away when premium is in use.

Any help would be appreciated, I am about to sell this thing.

[ccwhitener]

I have a 05 S. Just took it to a local shop today for a rattle when I accelerate. Especially up hill. I have had this problem for about 6 months now. When I get my oil changed it stops. We thought it was a heat reflector plate but there was no wear on it anywhere. I love my Murano!

[turbizzy]

Ok well obviously im not there to diagnose this issue but the loud noise your hearing leads me to beleive you have an exhaust leak. First gen muranos are notorious for cracked and even broken RH side exhaust manifolds, i've replaced 3 this month already on customer's cars.

But a cracked manifold won't necessarily cause a severe lack of power. This leads me to believe your exhaust system may be plugged somewhere. I have seem quite a few VQ35 engines with plugged catalytic converters causing severe lack of power symptoms and even creating a loud HISSING type of noise when accelerating, not sure if this is what your experiencing.

What you can try (you sound mechanically inclined) is removing the exhaust front tube assemly (Y pipe). Once you remove the tube assembly, try standing it on the inlet side end down and smack it on the ground a few times to see if some catalyst material falls out of the tube. If it does, then you most likely have a damaged/plugged cat. Take a small mechanic's mirror and look inside both cats to make sure the catalyst material is intact and not cracked or damaged.

[Linds]

Thank you, Tur!

I'm going to try to get to your suggestions this weekend. What you said makes a lot of sense, I really appreciate it.

I'll post what I find out then.

[Linds]

Alright, so one of the problems turned out to be what Tur said. It had a cracked exhaust manifold, which caused one of the cats to overheat, break apart, and throw its insides back into another cat. So, exhaust manifold was replaced, one cat was replaced, the other one was cleaned out. It runs much better, but it is not fixed.

It still has a spark knock, or what I believe to be a spark knock. What seems strange to me is when the sound is present, which is mostly at low load, i.e. I'll be cruising on the highway, my foot lightly on the pedal to keep a constant speed, and it will be there. Let off OR get on it, and it goes away.

It also still just does not run correctly, it still feels sluggish. I feel like it should also be getting going more than it does in respect to the amount of pressure I'm putting on the throttle. It does not start moving right away when I press the pedal, it has a delay. I don't know how much it is, it would probably not even be noticeable to someone who does not drive the car daily.

I recently got a code of P0037, which is for the oxygen sensor heater. I'm having trouble figuring out how to fix this. It seems as though just replacing the sensor may not do the trick. I checked the fuse (I assume it was the correct one: in the fuse box by the steering wheel, on the right, fourth from the bottom) and it was fine.

Please help, I just spent over a grand on this last repair and I don't want to keep pouring money into this car, but I don't want to be one $100 fix away and get rid of it, either.

Thanks!

[nitely]

I just replaced an 02 sensor of a 2001 toyota corolla 2 weeks ago. Its very easy to do. Its very possible that they may have damaged the sensor when they were replacing your cat or during the cats destruction. I would just get a new one and replace it. I suggest getting the oem one. The corolla is know for issues with aftermarket o2 sensors--except for the denso brand- and could not talk to the cars computer somehow. If you have the service manual then you know where it is. Its before the cat. bank 1 you get it from under the car. Is your code just the P0037? Go to autozone and get the reading for free and make sure you have it all.

[Warhammer]

Might want to address the P0037 first as the O2 sensor behind that failure is causing you to run too rich or lean. Fixing it will help.

If you still have it, might want to look at your head gaskets. Had another vehicle; i.e. 2002 Sentra 1.8L, that would knock and actually shutter if you lightly press on the gas pedal while cruising. Turned out that the head gasket was blown and allowing antifreeze to get inside the cylinder while hot.

[Linds]

Autozone is where I went to get the codes read, so, yes, P0037 is the only code.

I definitely want to address the code, I guess I was wondering if there was any way to tell if it is the o2 sensor itself or if it could be some wiring or the harness attached to it.

If I hadn't already spent so much money in repairs I probably would just get the o2 sensor to see if it helped, but right now, I'm wary of putting any more money at all into it, unless I know it's definitely going to help.

That's a good idea to check the headgaskets, too, I'll see if I can do that.

[turbizzy]

Just to clarify, the primary oxygen sensors on our engines are actually whats called "air/fuel ratio sensors" and while they look similar to typical 02 sensors, they work slightly differently and more accurately. Think of a wideband 02 sensor vs a short band (performance talk).

With that said, its weird that code is on now after the repairs. Not that its not likely it could be bad, but i've not replaced too many of those especially on Muranos. It could be possible it was damaged by either the faulty cat or maybe when they took it apart? Maybe take it back to the dealer and tell them the light has been on since the repairs were done and see if they can at least diagnose it for you for free?

I doubt its your headgaskets, i've not really seen any leak internally on muranos, not that it couldn't happen....

There's also a TSB for an updated transmission valve body for sluggish acceleration and a code the transmission sets thats not detectable with a generic scan tool, only the nissan Consult.

[Linds]

Thanks for all the ideas. I went ahead and just replaced the O2 sensor. I'm so glad it has really helped a lot. Unfortunately, while replacing it, noticed that there is an oil leak from...somewhere and the serpentine belt needs to be replaced. At least it is driving much better at this point. I'm going to continue to put fuel stabilizer and injector cleaner in and hopefully it'll continue to run well.

[spiked]

Originally Posted by Linds

Thanks for all the ideas. I went ahead and just replaced the O2 sensor. I'm so glad it has really helped a lot. Unfortunately, while replacing it, noticed that there is an oil leak from...somewhere and the serpentine belt needs to be replaced. At least it is driving much better at this point. I'm going to continue to put fuel stabilizer and injector cleaner in and hopefully it'll continue to run well.

If the oil seems to be coming from down around the base of the oil filter, then it's likely the oil cooler o-ring. The oil cooler is in between the filter and the block; the o-ring is between the cooler and the block. It apparently gets compressed over the years and starts to leak.

I just replaced my '05 Mo's o-ring - the leak had resulted in oil reaching the exhaust manifolds somewhere, and producing a burnt oil smell in the cabin - pretty nauseating. Glad that smell is gone!

It's an easy cheap repair - google "Murano oil cooler leak" for more info. I also noticed cracks in the drive belt when fixing the oil leak, and replaced that too. Also pretty easy (the power steering belt is a bit more of a challenge, but mine has no cracks, so I let it be and carry a spare).

Such repairs are much easier these days to DIY, what with all the info on the web, and if you have the shop manual PDF's...

spiked

[pbagstad]

My 05 Murano makes the same noise but also mine stops after I change the oil. Very weird