ive had this problem for months now after i installed my Greddy Sp2 exhaust. something beneath my car is rattling like a ************, especially in high gear and lower speeds when everything is vibrating more. its obviously my exhaust or heatshields. i dont think its the heatshield on my cat (which is coming off in days, so we'll see). it could be i didnt tighten the 3 rusted 13mm bolts hard enough ( i did it for a reason), or the piping is rubbing against the heatshield that run along the car. and i know its not from the exhaust hangers being loose. i cant stand this noise and its very embarrassing, especially when your car is such a looker.

 

well where is this noise coming from exactly the rear middle or what

 

anywhere from the cat to the resonator

 

lift your car on the jack stand or something, give a good shake on the exhaust pipe, also shake the cat, if you don't hear anything, now somewhere your exhaust gasket leaking.

when gasket leak, shake like crazy, whole driving cabin vibrate.

 

yea ill give it a try

hopefully when i put my omni power straight pipe on it will go away, you never know.