Last week driving on freeway, went over a construction bump at 70mph in the dark..didnt bottom out but felt it...anyways..now there is a vibration/rattle from 2500-3500 rpm's. Fist thought it was coming from underneath, exhaust??? Had car up on different hoists and everything underneath was rock solid. Tore the trunk and back seat apart,nothing, rear speakers nothing, only thing i havn't taken off is the rear quarters on the inside.....finally had someone lsiten to it while driving..they suggested it may be my brakes (am due, having done this week, waiting for pads to arrive) Nissan dealership said the shims on the brembos are prone to problems...and the other suggestion was that it may be my driveshaft???? With ebrake on andengine reving nothing...soon as it starts moving though there's this annoying *** rattle/vibration.....only between 25-3500rpm...soon as car is above that it stops..i have an appointment at infiniti but i want to wait till my brakes have been changed to rule those out..plus i don't really feel like paying 129 an hour for them to 'look' at my car....HELP...

 

probably bent a rim

 

Sorry let me be more specific..not a vibration through the car, more of a rattle/hum ...But why only rattle between 2500-3500rpm....has no reflection of speed or what gear i'm in...street or highway

 

the heat shields are known to rust out. do they use salt on the roads up there?

 

no man...we had snow this year but car was parked, actually stuck in driveway. And car was bought in phoenix, so this was the first snow it has seen. Had it up on two diff. lifts, no rust on the shields...heat shields around cats are fine to???? taking it in to mechanic tomorrow, having brake job done this weekend, see if i get anywhere with that!

 

My guess goes to exhaust as I used to scraped my shxt all day everyday. It only appears when reving from 2500-3500 is an indication of the exhaust. You probably hit it really hard but just don'r realize it. When my flex pipe was messed up I had the weird rattle around the same RPM as well, hopefully that helps.

 

so what did you do...do i need new flex pipe....unbolt and retighten exhaust cuz i really don't want to go back to stock... and the other thing is you can't hear the noise outside.