Well, I finally went and rebuilt my flex fuel line adapter.
Didn't put it on yet.
But tried to do some tuning without it, and no matter what I did it was commanding like, 10.3afr. realized that was due to the virtual sensor failing and reading incorrectly, and then even when I updated the tune and told it there's a physical sensor, (despite not having it connected), it was reading zero but still apparently throwing an error and telling it to run super rich ...
So I'm going to try and redo all that testing once I put the physical sensor back in and really see what it does.
I should have known something was up when I saw the stock tune running as rich as it was. I don't remember ever seeing those numbers previously.
In other news, the trans has finally gotten real close to what it was previously. Starting to feel real good and firm again. Haven't retuned the trans, just writing calibrations to the E(P)CM.