03 silverado, 6.0 with a tvs 1900, long tube hwaders, 3 inch exhaust... I keep getting a random check engine light. It goes on and off and stays off for days. Recently it's on, I had it scanned today at a buddys shop. This is what ca me up..

P0134 bank 1, sensor 1 insufficient activity.

P0154 insufficient activity

P0300 random misfire, this tho is tge last old history.

The 1st 2 tho keep coming up, the 02 sensors are new. Any ideas. .? I noticed with the scan tool that the one rear 02 doesn't change much. The other moves more but nothing crazy. The fronts both fluctuate pretty good, it runs totally fine. I see tho its real cold here now (20s) that the afs is in the 15.1-.3 range at idle.

 

you say new, were they of a good brand like denso, bosch? those codes are for both banks front sensors. headers most likely causing slow switching when cold.

 

They were denso, from rock auto. I just changed them when i put the headers on a few months ago. I didn't think of the headers making them change slow, the 02s are in different places too. A friend of mine is going to bring home a tech 2 so i can see exactly where the prob is. Hopefully i can get it sorted out, id like to get it done so i can put my new tune in with deleted rear o2s.