Originally Posted by elp_jc
If you checked all bolts and fasteners, it's going to be one of two things: internal rattling (manufacturing defect), or most likely, the resonance is making something else rattle. And most likely it's the heat shield somewhere. You'd have to get under there and touch the heatshield all over the place and see if it touches metal easily, and you can bend it back a little more to create a bigger gap. That's one of the drawbacks of an aftermarket exhaust. And you happen to have one of the quietest on the market. Oh, I'd also check that the safety straps (if you reinstalled them) are not touching anything. Good luck.
I looked at the safety strap. It seems like it has to to touch something? I wouldn't think a strap would rattle?
I'm 95% sure my exhaust is not touching the heatshield, cold or hot. All bolts are tightened... I do know my strap is touching stuff... I guess I'll fiddle with that.
Our cars aren't known to make any weird metallic/rattling sounds under 3k right? Just an exhaust install complication?