where are you getting your mpg's from? Sounds like your just reading what your computer is telling you in the car. Which in my experience GM cars over inflate this number big time.
to get accurate fuel mileage you need to fill your tank, reset your trip odometer. Then drive. On your next fill up you take the miles driven and divide by the gallons put into the tank and that gives you REAL WORLD MPG'S!
This is just about the only way to get an accurate number regarding fuel economy.
ZETEC Crew #26 SR #20 YELLOW BLAZE OWNERS GROUP#4
Moderator Pilot, 12 SE HB ╠╬╝, 2011 Ford Edge SEL AWD