New Air Filter, New Fuel Filter, Drained The water separator.

Pull the boat this weekend, 8.2mpg

Drove on the highway, no traffic, 55mph, 14.5 with cruise on.

I dont know how some people are getting 19 and some 14. maybe its the oversized tires.

Also---My trailer was making noise this weekend. Checked the bearings, and they are really bad. I jacked up a couple of wheels and could move the tire 1/2" in and out, so the bearings are hosed.

Could this be why its pulling so hard, or do the tires bog it down that much?

I have a 2001- 7.3 PSD, F-350, DRW, 4x4, Crew Cab with 4.10 gears. This truck is box stock. Best mileage I’ve ever gotten is 15 in the NC Mountains. I get 12 mpg on the highway at 75 to 80 mph and 12 around town. With a 41’ (#16,500) or a 36’ (#10,500) in back I get 9. These are real numbers in level So. Florida, not overhead computer numbers.

I agree you need to check to see if your speedo is calibrated. Also the overhead computer is good to compare different conditions but not to get real numbers. My Dodge's computer was consistently off by 1 mpg. You may be getting better than you think.