Mine has dropped from 13-14 down to 11+ MPG, and if I have to use 4X4 alot, which I have this winter, it will drop to 10+MPG. My biggest waste comes from the truck warming up this winter on it's 1st start-up. I do not like driving a cold vehicle. I'm glad petro has stayed under $2.00 per gallon in this area this winter. My wife's Scion TC usually gets 28-30 MPG she is down to 25MPG because she really doesn't like driving a cold vehicle.

 

Mine falls off too, I'm not sure if it is the fuel, or the fact that I spend more time warming up the engine.