Hello,

I have a cat back exhaust and am hearing a muffle noise or a splirting noise coming from the pipe that attaches to the catalyic converter coming from the driver side underneath, what is this an indication of? is that the resanator? sounds like coming from the baffle inside the pipe

 

exhaust leak -check the areas around the flanges (where the cat is bolted to the downpipe and of course the other end too) for carbon build up. or dont be scared and put that thing on jackstands turn on the car and check....