Hey guys I’ve had my 2013 G37xs sedan 7speed auto for over a year now and noticed I have this weird bucking between 1,500 rpms down to 900 rpms. It’s always when engine speeds slowing never when it’s going up. It idles around 550-600 and I have already done a idle reset after replacing the battery a few weeks ago. This really bothers me in slow traffic as it shudders the car when I’m coasting to a stop. Sometimes even going down hill I’ll watch the rom go from 600-1,200 back to 900 back to 1,200 on its own with no acceleration input or gear change.

I read the forums and found people had some problems with it above 2,000-2,500 rpm but when I floor it the car has no shudder and no problems.

Throttle bodies clean. I run premium. I feel like this recently came up after the battery swap because the alternator always added load to the engine stopping the shudder. And it never happens on acceleration only when coasting.....


ideas? I got no check engine light or anything closes Infiniti dealer is 2 hours away and Nissan is my go to.
Im considering putting some injector cleaner and hoping that’s the problem. I can take a video of this and post it if someone wants it. (Not interested in doing any tunes to the car)

 

My car does something like that, but I drive in manual mode 90% of the time. If I forget to downshift, the car does itself and doesn’t apply any throttle to rev match, lurching back and forth. Also, sometimes I’ll let off the brake, let it coast and as it’s coasting the RPM rises, haven’t seen it go above 1200 for me (when I had no maf’s, the motor ran to 3k without throttle input!!)

 

Hmmm I thought rev matching was still on in manual mode?

 

It is if you shift it, but if its cold and the trans isn't warmed up yet or you just forget to downshift, it'll remind you! It's not super violent, unless the trans is REALLY cold like you've just started the car- in that case i let it do it's thing, don't really wanna hurt the fragile thing!

In the case of just forgetting to shift, you might find the car drops a couple mph instantaneously.

 

Ya I don’t drive in the manual mode so I’m hoping someone has an answer to why the rpms dance around that low rpm range.

 

Video of the car at park. I quickly rev and let go completely to let the rpms drop down.

 

Have you changed trans and dif fluid yet 100k miles is max

 

My car has 67xxx kms (42xxx miles) on it. I definitely have not done that. And now the belts squeaking on start up and above 2,000rpms when warm. And it doesn’t go away at all. Honestly this is the worst car I’ve ever purchased like Renault ruined Nissan’s build.

(not sure if It is the belt but will be replacing the belt anyway and seeing if this garbage will last me a few years before I go back to Toyota/Lexus for life. not even worth the vq engine anymore and yes I am salty)


update: half my belts missing...... cool cool