I cleaned out my cat because I thought was clogged a couple months ago, And now my muffler is make in this popping sound when I first start the truck. Not every time but everyday! I noticed there's a small hesitation every once in while I guess what I'm asking is there anyway that the muffler it self can clog up, I mean I have already had the problem with cat. (Did a sea foam treatment and the small hesitation is defiantly passed) Any thought's are appreciated! About the popping noise coming from the muffler! Thanx AGAIN

 

If the insides of the catalytic converter broke up then they would have migrated to the muffler (no place else for them to go) and clogged it up.