Ok so heres the thing...I bought a 2003 g35 coupe back in sep 2005, with around 22k miles...since I got it till now, ive been hearing this rattling/vibrating noise. Its not really a rattling more like a thrrrrrrr. This is only heard when idleing. When i took it to the dealer, they replaced the cat and i thought that would have fixed it but i guess not When sitting in the drivers seat you can hear it very faintly, but when in the passenger seat it is felt on your feet and it is really loud. When listening under the hood the noise can not be heard. So i looked under the car to see if i could see anything but nothing, the noise is really loud under the car and inside but thats about it. I dont know what to do because I cant figure it out!!! please if you anything about this, let me know!!!!

 

Take it back to the dealership and have them listen to it... I think I have the same noise it comes right from under the car... but when I engage the clutch the noise disappears... I'm gonna take it to the dealer this weekend

 

yea i guess thats what im going to have to do....i thought i could fix it myself but i guess not...but thanks for your response!

 

Do you have a 6MT? sounds like a rattling throw-out bearing that occurs during idle but stops when the clutch is pushed.

 

no i actually have an automatic....

 

This sounds very slightly similar to the sound due to the rear axle needing to be re-lubed. You may want to ask them about it. Theres a service bulletin on it, so if you've never had it done it should be free.

 

i will definately tell them about that! anything i can try to fix it! Thanks!!