hey i just installed a full catback greddy sp2, everything sounds great except when I'm stopped at a light I hear a rattling noise, but when I start driving again the noise is gone. It sounded really bad when I reversed slowly. I have a rear lip and it is touching the tip of the muffler, could this be the problem? I also hear nothing when I have it on parked with the engine on.
I think I might trim the lip opening a little bit more, but i don't want to trim it its not the problem. Thanks

 

it could be touching on your heatsheild...mine did that until i ripped it off.

 

if it's a metal clanging, then it could be a loose exhaust connection, an unneeded heat shield, or if it's a softer sounding chatter, then it's the lip touching while the motor is at low idle due to the vibrations at idle or reverse.

 

where is the heatshield located at and do i really need it?

when you say loose exhaust connection, do you mean loose spring nuts?
it sounded pretty loud, but at times its louder than others and i remember several times I heard nothing while stopped at a light.

btw, is the vapors that come out of the muffler going to hurt my paint?

 

and it wasnt a metal clanging, it sounded like a knocking rattling noiserather... i might just cut the damn lip and see. thanks a lot

 

most likely the lip then, just ask someone to back your car up or idle and go behind the car and check for yourself. sound rattles are never definite, that's why we have ears to check, lol

 

you could also slightly bend the rear hanger alittle.... i wouldnt cut the lip IMO...

 

Yeah bending a hanger would much easier and less obvious to look at. Does your exhaust move much if you grab it and try to shake it? wait for it to cool down first lol...if so I would look at fixing that cause you never know what it could be rubbing against.

 

yeah, double check the source before you cut anything. and it doesn't look bad with it cut if you do it right using the original body line as the cut, it just looks normal. if anything, you can just remove the lip if it comes to it.

 

well its a pain for me to remove the lip since i used a lot of tape originally, so just trimmed around the opening a little bit and now while idle on drive i hear nothing!! woot woot. But... when I reverse I still hear it. Does the muffler shave more violently when the car is reversing?? Could there be any other issue since it's not a metal rattling noise but rather a plastic knocking?