Thanks. I'm puzzled by the missing gallon. I topped it off three times. I ran it down to 1/2-2/3 gallon remaining. 11.7 gallons. I've done 13.8 before. 91.5*13.8 = 1262 miles, a lot more than 1069 I just did. My F, 1/2 and E tank marks look like it wasn't full, but I filled, looped the parking lot, filled again, looped again and filled again. I don't know what else I could do.