I just bought a 2017 F250 4x4 Crewcab. Driving it around the Phoenix area I'm getting about 16mpg. That's going around 75mph on the freeways but also a lot of in town 35mph driving. I just hauled my 30 foot travel trailer to Washington State and averaged 10mpg. That might seem like poor economy but I drove at or slightly above the posted limit. Why? Because this truck has the power to do so. If the speed limit was 80mph I stuck pretty close to that. 75 and I ran closer to 80. 70 and I was around 75-78. A lot of miles were spent tooling along at the 80 mark. This is my first diesel and I had a great time passing other rigs especially while going uphill. My truck only has 3,000 miles on it and I was told that it starts to run a little better at the 15k mark. As a benchmark my previous truck, a 5.4l gas F150, averaged 6mpg on this same stretch but without the power to pass or even to keep up.