I made a thread about this awhile back but don't feel like looking for it. Anyways I mentioned a couple of months ago that in Drive (and drive only) while I'm idling at a stop light, the RPM will start dipping below 500 RPM for a second or two creating a shudder and almost feels like it will cut out. Then it will go back to idling above 500 RPM but even then the idling will never be constant like it should be at about 600 RPM, usually dipping up and down slightly almost every time after the car is warmed up. The shuddering occurs maybe every 4th or 5th time I come to a stop and last for a second. No problems in Park or reverse.

Then maybe once a week, I will have trouble starting up the car where it will cut out and stall and I usually have to press the button 5 or 6 times and lately I need to keep the foot on my gas to keep it from cutting out. It starts fine after that for about a week and then it will happen again almost like clockwork and sound like something is plugging up from the rough idle that periodically affects the start up. Someone in my original thread suggested that it was dirty throttle bodies that need to be cleaned or replaced which would make sense.

So I go to the dealer and they looked at it and said it's probably one of the sensors that need replacing. Well they put in the sensor and it didn't work. They did an "idle relearn" and it didn't work.

Has anybody had the same issues with thier car and how was it fixed. Are replacing throttle bodies expensive ot under warranty? It's 2011 G and still under warranty.

 

Clean the throttle bodies?

 

I had the same problem until I cleaned the TB's,there is a great write up int the DIY section.

 

Here is the before pic

 

I had the same issue in my 6mt cleaned the tbs and problem is gone. I only had 45k miles on my car at the time. Took all of 45 minutes easy DIY. I think ill do it every 6 months or so since it's easy and quick.

 

Thanks for the replys but shouldn't I get the dealer to replace them because they shouldn't be getting this dirty this quickly. I got less than 30k on this car and I have never had to have my throttle bodies cleaned with any other car I've owned so it sounds to me like its a defective part. I've never seen anything written in the manual stating these have to be cleaned regularly so its not a wear and tear issue. If they got dirty this quickly then they will get dirty in another 30 k. I remember someone saying in my original thread that they got thiers replaced because it was a known issue.

 

good luck getting them replaced. servicing the TB is normal and its not faultyness of the TB. depending where you live etc.. will dictate how dirty they get. maybe the dealer can look into the issue and just clean them?
my local dealer replace my rear break pads and resurface the rotors of my old g37 coupe for free since i stated a noise coming from the rear while reversing. didnt resolve the issue lol but i got new pads lol.

 

IMO, the G37 has a tendency to dirty up the TB's perhaps more so then other cars. The pics I posted are after 45K miles of build up and after a good cleaning it fixed the problem you described. I am not saying DIY or for certain this is the problem but to request the dealer to clean/replace under warranty.