At first very disapointed with the lly and fuel milage, my average was around 12 no matter what towing or mt. After 12K and first fuel filter change my milage changed drastically, went from avg. of 12 to 17 in the city and 18+ on the highway. Didnt really buy into the break in better fuel milage bit, but I must say I was suprised.

My 2 cents...