Klassickarguy
Newbie
1999 Tahoe 2wd 5.7L 134K. Just installed Flowmaster Muffler (Dual In Single out - to replace Stock Muffler). Sounds great and runs great but recently developed CEL with P0430 and P0442. I am wondering if it may have anything to do with the muffler change. I cant imagine cat is bad at 134K but maybe? Any Ideas?