I just got 42.3 MPG on a 433.3 mile tank. My car is not an SFE, and does not have active shutters. Gauge was estimating 42.8 MPG. I heard the tank getting near full, so I do not think that I underfilled.
Speeds of mostly 40-60 for the entire tank (only ~10 miles of interstate driving). Some city driving but mostly very early in the morning. AC was running for ~200 of those miles.
The estimated fuel remaining was saying that I may have been able to cross 500 miles on the tank, but it was too close to try for that mark.
2012 Grey Focus SE - Sports, Winter, Moonroof, Sync/Sirius