Picked up my jeep yesterday afternoon after having a new motor put into it. It was outa commission for a little over a month and I misses the heck outa it. I put about 30 miles on it and it ran great and sounded great. But the check engine light popped on and gave me "p0420" code. Does anyone think where it burned so much oil before its caused the o2 sensor to crap out? It ran great and still is even though the check engine light is on.
Do you have a "Cali" emissions setup with the 2 pre-cats?
Yep I've got the 2 precats then a big cat in the back. They were clogged up from the old motor burning so much oil that we knocked em out. I'm thinking maybe the o2 sensor has gone bad from all the burnt oil.