I have a vibrating noise from the passenger side area with car idling in reverse with my foot on the brake at a stop. If I take my foot off the brake and let it roll in reverse at idle speed it goes away. When I apply the brakes it returns. I do not get this noise in drive or in neutral or park or while driving. If I revv the engine in park I do feel a mild vibration but does not cause this noise. It started a couple of weeks ago and I thought it was exhaust vibration. I figured it clear itself after I had my exhaust work done. Well I replaced everything new- y-pipe, cat to muffler and its still there. any thoughts on this?

 

Do you have SFCs?

 

Yes. Its new 3"

 

Headers and aftermarket exhaust? My y-pipe would bump the subframe in reverse only, until I adjusted it.

 

I guarantee the Y-pipe is hitting the brace that goes from the SFC to the frame near the transmission tunnel. When you put it in reverse, the motor torques the exhaust into it, creating that heavy vibration and occasional noise.

My car does it too since I had the sfcs put in, I'm just glad it doesn't happen while driving.

 

Nick, I hope that's the problem. I'm gonna take it back to the exhaust shop Monday. I just don't understand it being the same before and after I had the exhaust work done. The exhaust before was factory. That's what has me confused. I checked, does have about 1/2" clearance to frame.
I have stock manifolds but probably same issue. Thanks.