just recently picked up my new to me 07 g35x. picked it up with 21k on the clock. i have noticed that sometimes when accelerating at certain rpms it sounds like there is a slight rattle or vibration as if something is loose. ive noticed it more often if i am initially accelerating somewhat hard, but not wfo, and then slightly ease off the throttle before the tranny is ready to shift. im going to climb under the car this weekend to change the oil and check, but it doesnt sound internal. more like a cover of some sort is loose. anyone else have any experience with something like this? thanks.

 

If you cant figure it out yourself, off to the stealership I might suggest. Car is still under warranty.

 

yeah ill see what i can figure out this weekend. although being that i just bought it i would hate to have to bring it to a dealer already.. it is annoying when i hear it considering these are well built cars and certainly not cheap either. thanks anyhow.

 

This has been discussed on several threads in driver forums. Most desribe it like a blow off valve sound.

I originally thought it could be a loose exhaust heat shield, but I still hear it ever so slightly after I swapped out my exhaust. The other plausible cause a member brought up is something about the transmission dumping pressure. I assume you have an automatic as well?

In short ... this appears to happen on all 07 and 08 sedans with 5AT. I wonder if it happens on the 6MT's? What about the g37 with auto?

 

try your 02 sensor on your cat. i had to tighten mine today. i thought i was the heat shield also