OK-- here is the issue, when its cold/cool outside i get this weird vibration and rattle in the engine compartment around 4500-7000 rpm, its only when its pulling in gear -i.e. just reving the engine wont duplicate the problem. I think it could be a motor mount, only because i cant really thing of anything else that is logical that would cause this rattle noise. Its an intense loud noise that goes away after a few minuts of warming up and reaching operating temp. I mostly notice it when i really get on it in lower gears.... Diagnosis?