My 2001 AWD needs a new muffler. A muffler shop wants $250 or so to replace it, which seems reasonable. Looks like I can buy a 2-piece kit for $150+ and do it myself when I finish my road trip, but it's not that much of a savings. Anyway, I'm getting a P0101 and 102 codes, which point to an air flow problem, possibly a restriction. The MAF sensor looks clean (I sprayed it) and the air filter is new, so I'm guessing it's the cat or muffler. The air 'tube' after the MAF sensor is intact.The muffler has patches and may leak a bit so it does need replacing anyway, but I'm wondering about the codes. Can a worn out muffler get clogged? I'm hoping the cat is fine, and I don't want to damage it if the muffler is clogged and I don't replace it right away. Thanks.