[rrbgtt]

I just bought my first diesel and ford at the same time. 2006 4x4 f350 with single rear wheels 373 gears. Everyone told me I would get 17 mpg unloaded and 12 towing. Not my truck. I average without load 13.5. When towing my boat ( 26' Twin Vee around 8000lbs full of fuel and geat) my truck got 8.2 mpg on the interstate running 70 mph with the cruise on. Is this typical, or is something wrong? Other than my fuel mileage expectations, the truck is great.