I have a weird sound coming from my exhaust. After I drive a while, and then park and turn off the car. I can hear this sound, something like a nail tapping on metal or something, coming from either the CAT or resonator. I can't tell which one. The sound started RIGHT after I put my exhaust resonator on. Any ideas of what the sound means and how to solve it?
Thanks.

 

My guess would be this.

When metal get hot it expands, then when you stop and turn your car off it cools off and contracts and it makes a creaking, or tapping sound.

Or am I compleatly off?

 

That sound about right b/c the resonator has all those weird metal pieces to restrict the amount of airflow, but the thing is that the sound start RIGHT AFTER I turn off the car. BUT, the weather has been starting to get a little chilly..
Do you think I should be concerned? I'm gonna get it checked up for my 30k tuneup anywayz..

 

If that IS what it is, then no worries. it happens on my car and I dont give a rats ass. the only thing I here now is the damn heat shield which I am considering ripping off.

If you want to rest your mind at ease, have the tech look at it when you get your check up. allways CYA. Better safe then sorry.