It sounds like it is coming from around the headers. When I look under the car, the exhaust is shaking VERY badly at idle. My guess is that its rattling so bad that it is making contact with the framework and sheetmetal surrounding it. What could cause this? It sounds like slapping two metals pieces together, and it is throughout the entire powerband. Very loud, I can hear it from inside my car, and when outside, you can clearly hear it.

It is the stock exhaust.

 

afternoon bump

bump!

I Hate You All!