Checked the unloaded mileage the old way on my new 2005 Chevy D/A. In town, 100 miles 13.8 mpg. 200 mile highway trip Saturday, driving fairly easy 55-65 mph it got exactly 19 mpg. The DIC was fairly accurate also. It was saying 13.5 in town and 19.5 on the highway. I also upgraded to Cooper Discoverer ATR 265-75 E rated tires. I couldn't stand those little 245 tires . Speedometer is off a little, at 60 mph my GPS says 61.2 mph. Before changing the tires the GPS read 59 when the speedo read 60. I'm liking this truck more every time I drive it.