Well I recently eliminated my catalic converter due to rust and other issues and completly redid my exhaust on my 95 accord 2.2 liter vtec . I straight piped it back but kept the stock muffler. Its nice and quiet and all sealed / rewelded back together but at 3000rpm I can hear a buzzing in the muffler. Like a real ricey raspey sound between 2750rpm and 3000 rpm.. I dont like it.... Any ideas? Is the stock muffler wore out on the inside ? I cant find it vibrating against anything so im not sure any help would be appriated.

 

Were you able to verify it was in the muffler and not the new pipe? The pipe could be rattling on the metal hanger near the rear passenger if your weld broke.

I guess what I'm trying to ask is if you crawled under there and found the actual location? If not, try to get someone to rev it in park until the noise starts and you can pinpoint it.

 

Right now im not 100% where the source is I have a pit in my garage so today im having a friend come over and rev it while I check it out. Im pretty sure all the welds are good. Im wondering like u said if it might be vibrating off a heat shield. I didnt know if mufflers wear out inside or what