Dang emissions!

Egadz

Member
Original poster
Supporting Member
Joined
Aug 7, 2018
Messages
37
Location
Calumet, MI
06 was throwing P0421 code. I replaced all 4 O2 sensors and cleared the code......and it stayed cleared for about 30 miles. I guess I’ll need to replace the pre-cats? Or all three cats? Any suggestions on where/what to replace them with?