A good friend of mine inhereted a roughly 2003 f150 that has a 4.2 in it with a slushbox, byt the axle code ( 19) it looks like it has a 3.55 open diff. Truck is completely bone stock and has only 29k moles on it and is in perfect condition, he inhereted it from his father in law when he passed away, and now he only drives it maybe twice a month, but due to fuel consumption, but when I heard that the thing was only getting 16 mpg on strictly highway runnning ( and I've known the driver for decades, he's pushing 60 and has a REAL steady foot) something didnt sound right
What would the *normal highway mileage be for a truck like this with a civilized driver, and what might be causing a reduction in mileage?
One hint, While we were visiting, he asked me to check out a pulsation in the brakes, and I found surface rust that had settled on his rotors causing his pedal to pulsate when braking ( which I imagine was also dragging going down the road ) I got in it and rode the brake lightly for a couple of blokes to skin the rust off and that got rid of it, but I couldnt imagine surface rust lasting on a long trip.
Thanks
What would the *normal highway mileage be for a truck like this with a civilized driver, and what might be causing a reduction in mileage?
One hint, While we were visiting, he asked me to check out a pulsation in the brakes, and I found surface rust that had settled on his rotors causing his pedal to pulsate when braking ( which I imagine was also dragging going down the road ) I got in it and rode the brake lightly for a couple of blokes to skin the rust off and that got rid of it, but I couldnt imagine surface rust lasting on a long trip.
Thanks