Poor Gas Milage from 2006 F-150
I have a 2006 f-150, only 25 000 km and the gas milage is poor. Firts when I got the truck highway milage was in the 18-19 Liters/100km range and now its down to 15-16 Liters/100km. I have the truck serviced regularly and 100 km ago I replace the air filter and still no improvement in gas milage. Any sugestions on what may be causing my decrease in gas milage?