I took a short trip last weekend into the Sierra Nevada mountains in northern CA. I went from sea level to over 7,000 feet.....and back. Average mpg for the 340 mile round trip was 20.5. 17 something on the way up and 23 something on the way down for a 20.5 average. I cruised between 65-75.....85% freeway. I am continually impressed with this truck!!!.....John