[LAWright]

We have a 2003 Murano. On a recent trip to Florida, we started experiencing what I'll call "rpm twitching". While maintaining a consistent speed between 75-80, both manually and with cruise control, the tach would jump up & down between 2200 and 2700 rpm. It was an intermittent problem while cruising the interstate during the trip. This hasn't happened since we returned home due to city driving, but we took it to the dealership anyway to have it checked out. Of course, the computer said everything was fine, but the problem wasn't our imagination over 1600 miles of interstate driving. Has anyone else ever had/heard of this problem? Any help would be greatly appreciated.

 

[Stoker]

We have a 2003 Murano. On a recent trip to Florida, we started experiencing what I'll call "rpm twitching". While maintaining a consistent speed between 75-80, both manually and with cruise control, the tach would jump up & down between 2200 and 2700 rpm. It was an intermittent problem while cruising the interstate during the trip. This hasn't happened since we returned home due to city driving, but we took it to the dealership anyway to have it checked out. Of course, the computer said everything was fine, but the problem wasn't our imagination over 1600 miles of interstate driving. Has anyone else ever had/heard of this problem? Any help would be greatly appreciated.

When the RPM started to go up and down did you notice if your speed cycled up and down also to match the engine RPM?

 

[njjoe]

LAWright-

I have not experienced that problem nor do I recall reading about it.

If it had been an unusually hot day I might think the CVT adjusted the ratio to a numerically higher ratio to put less of a load on the engine to prevent an over-heating condition. I am not sure if that logic is programmed into the MO's ECU.

-njjoe

 

[Kris]

Yes, I experienced this problem. A number of this forum members reported it as well.

What you were experiencing was TQ (torque converter) not locking up. It usually goes away when you stop, turn the car off and then on again. It happened to me twice. The first time I drove for 100 miles or so with car behaving like that. Then I stopped, turned car on off and on and things got back to normal. The second time I took the car to the dealer and they retrieved fault code. The TCU (transmission control unit) was replaced.

You have experienced similar problem, as there was no fault code you should be OK. Till next time. But now you know what to do….

 

[LAWright]

Thank you very much for the replies! Since this is our daughter's vehicle, we are very anxious to get to the bottom of problem and get it fixed so she doesn't get stranded on the road.

My husband's initially speculation was that it was the CVT, specifically the pulley on the drive line side not locking in the correct location. However, the Nissan dealership nixed that.

To Stoker---although you could "feel" the rpm fluctuation in the engine, the speed stayed pretty constant.
To njjoe---it was actually very cool (~50 degrees) when the problem started.
To Kris---we stopped several times on the trip, but the problem never stayed away for long. How long did it take yours to "reset"? Could the TCU be failing, but hasn't really failed yet, hence no fault code?

Again, thanks for the replies!

 

[Kris]

We stopped at a rest stop, had a cup of coffee - so I would imagine it was no more than 10 min.

I am sure the symptoms youe described is the TQ not locking up. The TQ is controlled by TCU. It this is not TCU it might be a loose connection.

 

[LAWright]

We stopped for about the same, but the problem came back. Our plan now is to take it back to the dealership and strongly request that they replace the TCU now---sounds like it will be now or later, so might as well do it now.

Thanks again for your help.

 

[Tyler_Canada]

We have a 2003 Murano. On a recent trip to Florida, we started experiencing what I'll call "rpm twitching". While maintaining a consistent speed between 75-80, both manually and with cruise control, the tach would jump up & down between 2200 and 2700 rpm. It was an intermittent problem while cruising the interstate during the trip. This hasn't happened since we returned home due to city driving, but we took it to the dealership anyway to have it checked out. Of course, the computer said everything was fine, but the problem wasn't our imagination over 1600 miles of interstate driving. Has anyone else ever had/heard of this problem? Any help would be greatly appreciated.

At that speed you are nearing the point where the torque convertor won't lock up at all due to the amount of power required to overcome air resistance. If you had a strong head wind or were climbing even a moderate hill, either could cause the torque convertor to unlock temporarily to give a bit more power.

 

[Enforcer]

Re: Re: CVT problem?

At that speed you are nearing the point where the torque convertor won't lock up at all due to the amount of power required to overcome air resistance. If you had a strong head wind or were climbing even a moderate hill, either could cause the torque convertor to unlock temporarily to give a bit more power.

Eh I'm not sure about that. The CVT will automatically spool down as needed, don't think the converter will unlock. Also never had a problem when I did this:

http://www.nissanmurano.org/forums/showthread.php?s=&threadid=1119

And this is interesting:

http://www.nissanmurano.org/forums/showthread.php?s=&threadid=245

 

[njjoe]

Tyler_Canada-

You may be right in your supposition. As per the attached chart from the Service Manual, you can see the TC lock-up range is speed and throttle position dependent. Traveling at 75 - 80 MPH (as LAWright was) it is possible to be at the threshold of unlocking the TC if you are light on the throttle.

-njjoe

 

[Enforcer]

Eh I don't know, with a strong headwind at that speed your not light on the throttle. Maybe with a strong tail wind going downhill...or maybe a semi passing and getting a draft.

Still, I made a 1200 mile round trip in 03 and 04 and several shorter highway trips. What LAWright explained I have seen. But its the CVT spooling down as needed not the TC unlocking.

 

[Tyler_Canada]

Regardless of the mechanics behind it, when I drive 75 mph, I'm at 2000 RPMs and when I drive 85 mph, I'm at about 3000 RPMs. Somewhere in there is a large jump, and I've noticed that if I'm at around 80 mph and I go up a slight hill, the RPMs will jump and then drop back down once less power is needed.

 

[Enforcer]

Exactly. So here's a question then.

LAWright, does the twitching coincide with a slight incline, a wind buffet, or a car passing? Basically does it coincide with anything that changes the combined load on the vehicle?

If it does then thats normal. If it doesn't then that's a problem and welcome to the "dealer can't replicate it" club.

 

[LAWright]

Enforcer:

Sorry for the delay in answering---didn't log on while traveling this weekend.

We originally noticed the twitching along I-20 between Birmingham and Atlanta close to Anniston and in south Georgia along I-75. Somewhat flat landscape there. At another point we were traveling along the FL turnpike on very flat road and maybe a crosswind. The twitching was noticeable with either the cruise control engaged or with manual throttle. So I would say there was no increase in the load in the instances where we noticed the twitching. It was simply trying to maintain the constant speed.

Unfortunately, we seem to be in the "dealer can't replicate it" club for now.

Thanks for your input.