Hi all,
Happy spring!
My 2006 G35 has a slight roughness/vibration which is noticeable in the steering wheel and my driver's seat during idle, along with a subtle fluttering. It only happens when idling, not when driving. I took it to the dealer today and of course they can't duplicate it. The car has usually been so quiet you can't tell it's running but not anymore. Any thoughts?

 

I would look for a vacuum leak or something to do with your spark plugs. How many miles are on your plugs? Might be time to change them.

It could also be a dirty MAF which is super easy to clean.

 

Thanks. Dealership said even though they couldn't replicate the vibration they did a few "tests" and everything seems fine. Not sure what tests they did. I recently had the alternator belt replaced as regular maintenance because my regular mechanic said it had a crack in it. Could the new belt be causing some type of rough idle? The car has 45K miles so I assume the plugs are original. How do I check and clean the MAF?

 

How often are you supposed to replace spark plugs?

 

I am beginning to think this is an exhaust fluttering. I put my ear down by the exhaust pipe and I swear it's coming from there. I also smell a slight rotten egg smell (catalytic converter?). I am bringing it to my local mechanic tomorrow for a second opinion. Dealer can't replicate the fluttering. Usual response when I bring my car in for something.

 

Have you ever cleaned the throttle body? Could be build up causing the idle to fluctuate as the TB opens and closes to let enough air in for idling. My 06 does this too every so often. It's more noticeable at cold idle situations. I wouldn't really worry too much about it though.

 

The MAF is located inside the plastic attachment that attaches to the back of the airbox. You will need a tamperproof torx bit to unscrew the 4 little screws that hold it in then it just slides out. Buy some MAF cleaner at your local auto parts store and just spray it down. Don't use a qtip or anything that will physically touch the wire in the sensor or you will have issues.

 

when i intalled my new plenum i was getting a lot of vibrating/ideling and even stalling all it end up being was the gasket for the throttle body not being centered correctly

 

Does anyone have a picture of the location of the throttle body, where it unscrews with the torx bit? The guy at the auto parts store said if you clean the throttle body and one little speck of dust gets in forget it, you're in for a big headache. Is it really this sensitive to being taken out and being handled/cleaned?

 

You will hear it coming from the exhaust because the exhaust system transfers the noise from your engine. First step to rough idle is always throttle body and mass air flow cleaning. Both fairly simple.

The throttle body is sensitive, but there's a DIY here that's very careful in explaining how to handle the throttle body. I would recommend that to help you out. Throttle body cleaning is very helpful to the smoothness of the engine.