Just wrapped up a 3k mile road trip to go camping with a friend. Kept track of the expenses (we're splitting the costs) along the trip. At every fill-up, dollars, miles and gallons were recorded. We had the bed of the truck packed full of camping gear (tents, clothes, three weeks of food etc) under a topper plus a small (3' x 5') trailer with folding tables, cots, chairs, stove, propane tank. The two of us up front, plus a 70-lb dog.

Here's the weird part: The lowest mileage was across relatively flat western Nebraska and southern Wyoming (typically 15-16), and the best mileage was: 18.65 going west and 19 going east over Teton Pass, which is 8-10 miles of 10% grades and the rest typical mountain pavements.

Overall, the trip averaged 18.63 MPG!

 

Damn!! Nicely done! Any relevant work done on the truck, whether just close attention to maintenance or mods?

 

Nothing unusual. Simply turned off cruise when in hilly areas and let my speed go up and down.

 

Good to know that these trucks don't have to get V8 fuel economy!

 

V8 fuel economy???? Most V8 are coming with 8 speed tranny to get better gas mileage.

 

I am guessing you were going less than 70 mph. These trucks get better gas mileage when the speed it reduced. I also just finished a 3,100 mile road trip which included a lot of off-road in Idaho. My best mileage was 18.5 mpg at 70 mph. I had no trailer but was loaded with at least 800 lbs of gear and supplies. My worst mileage was 12 mpg in low range 4WD with a lot of very steep climbing. I think my worst highway mileage was a little over 17 mpg with some mountains to climb and I kept it at 70 with cruise control.

One thing I have found over the years is a head wind will lower gas mileage a lot, especially when towing. Tail wind are always welcome.

 

I limited myself to 67 MPH, even in Wyoming where it's 80 of the superslabs. I'd push it faster if I need to get around a semi governed at 65 if traffic was creeping up behind me.