can a cloged cat cause your car to make poping sounds at idle (kinda like backfiring) ?? but i noticed that around the donut gasket area it sounds like there is a leak ?? but i dont think a leak can cause the backfiring noises, can it?

 

mine did... especially when it was turbo'd. leaks sounded weird like popcorn under the car.

 

Yeah, I run no muffler at the moment, and my car makes all sorts of burble-y, backfire-esque noises. Stock 1 inch exhaust pipe - muffler = sweet!