i had my wifes expedition in at the ford dealership to replace 2 coils and they reprogramed the pcm to the latest calibration and since then the gas milage went from 19mpg to 14 mpg and they said the pcm wouldnt cause the milage to drop and said the fuel filter could be bad i thought a bad filter it would run rough .but it was getting great milage before i took it to them.any help would be greatly needed. thanks billy