Codes triggered about a week ago. Reset with the GAP tool. Came back on this morning. Both set during moderate acceleration on the highway with outdoor temps around 65 f° and engine up to temp after 5-10 mins of highway driving.

checking the live values, my upstream values range from -320mA to 350mA and
my downstream range from 0.1v to 8v (unless I’m accelerating or coasting).

i reset the trouble code this morning while idling in the parking lot, within a minute my idle RPM went from ~650 to ~1200 and the viscous fan was at 1400rpm. Coolant temp stayed steady at 192 f°. No change after 5 mins and I shut it down. Had to get into work.

could this be a case of switching from winter gas to summer gas? I’ve been strictly filling up with Costco premium gas for the past 4 years.

 

Crickets.

Then CEL has t come back. I’m going to assume just a change in gas type caused the engine pcm to freak out while adjusting long term and short term fuel trims.