Alright so i recently installed my Evo2 cat-back system and everything was fine for the first day or so, but then a metallic buzzing sound started coming from the resonator whenever I accelerate. However, it's only in low RPMs where i suppose the frequency makes something inside the resonator rattle... I've taken the exhaust apart in sections ( ran car w/o muffler and still made noise...ran car without midpipe and no more noise) so it's somewhere in the middle. It's only been 4 days since i've installed this system.

Does anyone else have this problem? Or have you had this problem and gotten it fixed? Any ideas on what it could be? Any help is appreciated. Thanks!