Hello I have a 08 G37 S 6 speed and have a problem so my idle goes up and down on Its own on neutral after a couple of minutes being still. My car has 90,000 miles so I took in for a brake check and asked the techs to clean my throttle body and they checked it out supposedly and they said it didn't need to be cleaned, this was a Fletcher's witch they a chain of tire and service for cars in AZ. So I wil post the link to the video and I would like advice I'm not very mechanically inclined, anyone recommend taking it to another shop or should I directly got to Infiniti I just don't want to spend the money at the dealer and rather go to a trusted shop. I know of one in Phoenix that specializes in Infiniti and Nissan. What do you think it can be? Here's the link
http://youtu.be/5Hz_73GCnVo

 

I was going to say it might be the ac pump kicking in, but after looking at the video I would think it is something a bit more involved. It's sooo difficult to say because with no engine error code or something like that to start with, it's a big area. I would check the Mass Air Flow sensors first off. It might be something simple like the connection to one of the sensors is bad or loose. If it was something that was fine one day and began acting up the next day, hopefully it might jog the mammories a bit.
Good luck with it dude

 

Do you have an aftermarket intake? The reason I ask is because I have Fujita short ram intakes and I got that problem when I decided to clean the throttle bodies and MAF's. I got the code, reset it and it came back about 5 days later. Performed the idle relearn and pedal position according to the FSM and the code came back. Started looking at the intake side for possible leaks and stuff that seemed out of place and noticed that one of the OEM PCV breather hoses had a 70 degree bend preventing normal flow. Got a silicone hose kit from Z1 Motorsports and the problem went away. Smooth idle and no codes since February. (That's when I got them)

 

Do you have an OBD reader to see if there are any pending codes? Potentially could also be a vacuum leak. Any hoses leaking or not connected properly in the engine bay? When the shop was looking at your throttle bodies do you know if they disconnected them? I think I remember reading something about making sure not to disconnect them when cleaning/removing them or it can cause idle issues.

 

I actually sold the car just read the responses. It was a very weird instance only would happen when on idle for long period of time, definitely could of been a vacumn leak I'm sure, I though it was the TB'S dirty but I guess not, weird thing is car never threw out codes I even went to auto zone and it was good, not even check engine lights. I actually don't think it affected performance at all either but it might of. Thank you all for the responses