Thanks Red, I did just that. Still hasn't resolved the problem, but I ran it out, added 7 gallons to put it at about 1/2 tank, soldered a 600 ohm pot in series with the sender & adjusted it to read 1/2 tank. 2 drive cycles later, all codes cleared (completed monitor tests). I still haven't figured out what's goin on, but if I can get the gauge to read "empty" when it's empty I'll be happy with that. When I get it working properly I will post the final result to share. I appreciate everyone who contributes to the forum!