I think it's fixed
I win the dumbass of the year award though...
I said I checked that ground location, which I did, but only visually. It looked nice and tight. If I had pulled my head out of my ass and actually tightened it I would have noticed that it was just a tiny bit loose. Tightened the bolt, pulled the neg battery cable to reset things, put it back on and she fired right up.
Lesson learned, trust the Toms
*hangs head in humble shame*
It also explains the speedo error since that is the ground location for the speed sensor.