I spent the last 2 days getting my new Exahust system on my car and I just started to pull out of the driveway and I kept hearing the banging noise over and over again as I drove forward and then as i drove in reverse the same noise repeated. I looked under the car while someone drove it slowly forward and i saw the I-Pipe boucing around agaist something....WTF? Have any ideas? I'ts a 3" Exhaust, but I've never heard of anyone having this problem before, it a dynomax 3" I-pipe and a dynomax 3" Muffler....any ideas?

 

Did you change your cat? I installed a used 3" catback 3 or 4 years ago. It's all bolt in with clamps, so I had to use an adaptor from the stock Y pipe to the 3" inlet Cat. I recently adjusted it for ground clearance and eliminated the rubber mount at the transmission . I used a solid piece of exhaust hanger. The newer cat is slightly longer and changed the angled sections length, moving the intermediate pipe closed to the DS. It doesn't hit but it IS closer. you may need to make some change at the cat's inlet or outlet side. I'll get around to that some day. For a DD mine's OK.

 

I did install a new 3" aftermarket cat...that could be it because of the length offsetting the rest of the I-pipe close the the center of the car...I'll have to check that out

 

Well, that was it...the I-pipe was hitting the end of the driveshaft (where the driveshaft widens towards the back). It was rubbing on the edge of the bolt that sticks out....I loosened up the exhaust hanger and pushed the muffler over towards the passenger side and it moved the I-pipe over just enough so its not rubbing...