I've been messing around with stoich but I turned it back to stock a while ago.
Could it be dirty carbonized plugs? Or maybe carbonized o2 sensor?

Wow man, appreciate it. Thank you.wcs wrote: ↑November 21st, 2023, 12:45 pm You should see a change in the Actual AFR beyond 15.1 - 15.4 especially once you go into open loop.
Walle has posted a good write up / discussion you can see in this thread
viewtopic.php?f=25&t=4316
Hey, sorry for answering this late, but yes, I did check everything mentioned, and I had no luck. I'm suspecting of a faulty upstream o2 sensor.