I have the F-350 with the 6.2 gas engine. Just returned from a 5000 mile trip with many mountain passes. Towing a 12,000 pound loaded high profile 5er. My average MPG driving about 63 MPH was 10 MPG. with a range of 7.9 into a 20+ MPH wind to about 12 MPG. Even got 99 MPG coasting down from Mount Hood. Generally there was plenty of power but it shifted down to 3rd gear on many passes and even 2nd a time or two. The tow haul feature worked well for shifting and downhill braking. Down long steep passes I used the brakes maybe 10 - 15% of the time. My first long tow with the 6.2 after junking my 6.0 diesel. I was 100% happy with the 6.2 gasser.