AFR misleading? Plugs tell a better story?

TT5.9mag said
See if you can get some compression test results. Can’t tell for sure but number 3 plug looks wet to me and may be a source of a “misfire at idle”

Hopefully tomorrow for compression test.
Agree 3 is darker, but not wet.

dano said
You can foul O2 sensors as well. So if you ever ran pig rich, they can get sooted up. Clean with compressed air.

Don’t remember running really rich. Maybe I’ll get another sensor.

mopowers said
When's the last time the AFR gauge was calibrated? Most of them recommend annual calibrations.

Just this last Friday, after pulling plugs.
Same numbers with new plugs. Innovative AFR