Hi there, first time posting here. Sorry if this has already been posted about before but I’ve been searching for a while and haven’t found much.

Having a start up issue with my truck and a code 21 for o2 sensor. On a cold start the truck will idle fine but will be sputtering a bit on and off for the first minute of driving. On a warm start the truck will idle poorly, I have to rev it fairly high to get it to go and it’ll bog down and fall on its face. It’ll do that for a minute or so and then be fine. I took the o2 sensor out and cleaned it a bit and it was fine for an evening but was acting up again the next morning. The truck fires up perfect and drives great besides the minute after a start up. Could this be anything besides the o2 sensor causing this issue? I ordered a new sensor just seeing if there’s anything else it may be.

 

did you check the injectors ?