Just took a 9 day trip to Yellowstone and Cody Wyoming. 2500 miles!
I've come to the conclusion that the shape of the Wrangler body would make a very efficient sail, or perhaps kite. Gusty cross winds both directions made for some white knuckle action.
Interestingly using their 85 octane fuel and traveling the Beartooth highway (The Road itself is the highest elevation highway in Wyoming (10,947 feet) and Montana (10,350 feet), and is the highest elevation highway in the Northern Rockies.) I had the best mileage. I actually hit 19.7 mpg! Too bad there was so little power I was floored and doing 50mph most of the time LOL Elevation really kills the power of the 4.0, and I had the Jeep really loaded with camp gear as well.