Now mind you this was almost all down hill, almost all interstate, after a full synthetic 36,000 oil, transmission, front and rear diff, and transfer case fluid change, and with a new Amsoil air filter, I got 21.4 mpg from Burnsville, NC to Duncan, SC traveling at about 70 mph on US-19/23 to I-26 to I-85 (about 105 miles).
The best previous mileage I ever got was pre-lift, armor and larger tires, from Edisto Beach, SC to Charleston, SC, at sea-level on US-17 (about 50 miles) doing exactly 55 mph (lots of highway patrol just looking for out-of-state tags!!!) was 20.5 mpg.
Now, I know I have a lead foot on the highway, but I still don't see how those out there with ARB bumpers, 245/75s and more armor than me are getting 22-23 mpg on the highway. Unless they are traveling at exactly 62.5 mph.