05 COUPE, rattling sound at 4000rpms?
 

I got a 05 civic coupe and took off my stock cat back and muffler with a 2.25" custom cat back with high flow resonator and magnaflow muffler. The shop welded it on. When i first tried revving it, i think i revved it to 4000 plus before once engine is warm and no rattling or vibrating sound of the pipe. Now its been a month and when i rev my engine to atleast 3500rpms and down, it sounds reaaaal nice but once it gets up to 4000 i hear a rattling, vibration sound like my pipe is hitting something? I dont know whats causing this? I am obviously gonna ask the shop to do something but can any of you guys give me advice or atleast know wat i should do?

ALSO, my car is auto and sometimes i drive on 3rd gear on the streets and change it to 4th and i get a little rattling sound or gears scratching sound? but i think its the pipe because my windows are rolled up so it sounds like the gears arent meshing together? :confused:

Best bet is to take it back to the shop that did the work and have them take a look at it.

Your other option is to jack the car up and set it safely on jack stands on level ground. Slide yourself under there with a flash light and rubber mallot, start tapping the pipe with your fist in different locations, also try grabbing the pipe and shaking it to try and duplicate the noise. If you can duplicate it, you may find it's something minor you can fix on your own, like a loose piece of heat shield.

Good luck. :)

yeye i did yesterday. just a loose hanger the man sed