Any of you every run into this? I know it's exhaust and I know it's usually the downpipe (bad cat or O2 sensor) but mine is very sporadic. It will go off and go a few weeks without another. Anywhere from week and a half to 2 months and been happening since August. Any ideas?

 

that happened to me. 0420 is the rear O2 sensor. just get a park plug non fouler or one of those "L" spacers and you'll be fine. the only other thing i came across was i got rid f the 0420 code, but am throwing the 1030 now (which is the front sensor). i have full exhaust and think that the weld gasses probably "clogged" the front sensor, which makes the rear read bad as well.

i have that all here
https://www.cobaltss.net/forums/problems-service-maintenance-69/p0130-cel-help-197243/

 

I have no idea what you mean. and the pics are gone from that thread.

 

Bump