Rough Idle and vibration when accelerating
 

Symptoms:
1. Car idles rough and at times the vibration can be felt in the drivers seat/door as well as near the gas/brake pedals. Some times its not as bad and I can deal with it but other times its very noticeable and hard to ignore.
2. I have noticed that when accelerating, I can feel the vibration increasing near the pedals. I think I can hear the engine being louder as well but maybe thats in my head.....


My car is stock, has 52k miles and I only use premium fuel. I took it to the dealer and they claim every thing is set to factory settings and they cannot find any thing wrong with it.

Has this happened to any one here? Any guesses on what is going on? The vibration is driving me nuts! In December I had similar symptoms with rough idle before and the dealer was able to find a bad MAF and replaced it. All went away and was fine for 2 months and now its back but symptoms are a bit different and the vibration can now be felt when accelerating.

The only thing I can think of that happened 2 months ago was that I drove over some hard snow and as a result, the car's bottom plastic cover started coming off. I had my local mechanic look and cut a piece of the plastic cover off. Car was fine after that and drove fine for one month and now this started. The dealer said they looked underneath and couldnt find any thing wrong. Any help is appreciated. Thanks.

First thing i would recommend is to perform the Throttle Body cleaning as listed which improves the rough idle with a GREAT margin! Then come back and post your problem here if it does not go away.

^ agreed.

1. do a TB cleaning, kool yaar provided the link. this may even fix your #2. problem

2. If your vibration is at a certain speed range, 40mph or 60kmh, and it feels like the tranny slips and reconnects, give or take, you will need an ECU reflash, as I had the same issue.

^What he said. I keep forgetting to have this done, and am also living with rough idle.

check your engine/transm mounts, clean idle air control valve/throttle body to start with.

I will try doing the TB cleaning this weekend. The rough idle I can live with, its the annoying rough operation of the engine when accelerating thats annoying me. Its like whenever I give it gas, I can feel the engine working through my feet.

I had the same thing, sometimes my car jerks and stall, i have same model as you are and it's 5AT, do that and you should have no problem with it at all, it should disappear, and keep us updated when you do it.

Your car is obviously not within spec if there's rough idle and vibration on acceleration. The dealer's answer is unacceptable. Dealer uses that excuse a lot to get out of doing anything. I'd insist they get it resolved, or take it to another Infiniti dealer. I assume you're still under warranty.

Taking mine back on Thursday, still idling down to almost cutting off. Getting freakin annoying! I'll recommend them clean the TB, I know its gonna cost a pretty penny!

^ Do it yourself or get a friend who knows how to do basic maintainance to do it, its very easy and very effective and will get rid of the idle surge where the car almost cuts off.

I just texted my mechanic to see if he can get me in tomorrow and clean them. Thanks, stay tuned. I'm getting waaay to familiar with my Infiniti service advisor. She is cool and all but I'm tired of seeing her LOL.

^ wow you txt your service adviser... now thats way too familiar but should help you get things taken care of quicker. ;)

It could be related to engine/tranny mounts or perhaps Throttle body/fuel/air issue. If it is related to throttle body you would see the rpm changes at idle. If you don't see that it is most likely engine or transmission mounts. Maybe when you bottomed out your car.

I agree with the guys that mentioned engine/tranny mounts. It definitely sounds like they are worn. Have them checked by your mechanic and if they need replacement let the dealer do it.