i have a greddy ti-c catback and have had zero problems with it. i installed my megan racing manifold, o2 housing, downpipe and test pipe on monday and today i hear this rattling sound at idle. i cant really hear it once i give it gas but as i am just sitting there it sounds horrible... anyone know what it could possibly be?

 

It is probably your downpipe hitting the front cross brace.. put some washers.

 

nah i dont think its that the down pipe cleared it by about a half inch. its more towards the back of the exhaust... around where the resonator is on the TI-C

 

FIXED! the bolt on the ti-c exhaust where the o2 sensor should go was loose and rattling around... good thing i didnt loose it