Failing Emission
 

I just got a Maroon 94 (I believe) Blazer w/ a 4.3 engine. It can't pass emission and is limping badly. I'm gonna replace the cats and O2 sensors (should only have 2 right?). Are they are other critical emission parts that I should be aware of, if I don't pass emission? Also wondering if I should install OEM Cats, or are there performance cats availble for slightly more. I'm thinking of swapping out the muffler, but I'm not sure how it will sound. I've got a 94 Caprice w/ an LT1 engine, w/ 2 1/2" exhaust and Summit Turbo mufflers, it sounds great. I'm just concerned a 4.3 engine might sound "rice".

RE: Failing Emission
 

well idk about the emissions...but there are high flow cats that dont restrict exhaust as much.

RE: Failing Emission
 

id consider putting new plugs and wires in it also. could have a cut plug wire that could be causing the truck to run poorly. would also make you fail emissions as well