I have a 2004 G35 Coupe. I have been having a very annoying low pitched humm coming from my car on deceleration between 70-80mph. It does not make this noise at all upon any kind of acceleration.

The car is bone stock with the exception of a JWT clutch and lightweight flywheel and a Stillen cold air.

It has been to two different Infiniti dealerships three times now and the problem is still not fixed. They have replaced the rear diff and front wheel bearings and still no luck. Does anyone have any recommendations on what else to look at?

Thanks