random conversation - P0171

Car set this code, so I used some MAF spray. Right after that, it showed P0300, 01, and 04 codes, but I cleared them all and none have come back. I think the misfires could have been overspray? I drenched it good.

Regardless, I still hear a misfire/feel a shudder. Very rhythmic. Idles smooth for ~10 seconds, then a slight miss for ~5 seconds. Was doing that over and over, with/without AC.

The next part to check/replace in the diagnosis process is the OX1 sensor, then injectors. And, I don't mind doing that. I have spares, Just wondering if anything else lines up better as the cause of that rhythmic shudder. The car runs/drives fine otherwise, although I expect the codes will reappear soon.

 

Thanks, Josey. This car had an aftermarket cat when I bought it, but the vacuum canister hadn't been hacked so it showed a CEL. I added the vacuum canister back, but maybe it's leaking. I've driven the car ~30m since I cleared the codes and they still haven't come back, but I still feel the miss at idle, just barely. I'm going to drive it again today and see how it does.