I was a little curious and found that people get between 11-19mpg realworld gas mileage in this thread:
I have a '91, 2wd, reg cab and I usually get 13-15mpg for regular driving and 17-18mpg highway.
My truck weighs 2,000lbs less, has a 2.4 liter smaller displacement engine, and gets about the same gas mileage.
What about you guys? Does the F150 get the same gas mileage?