It really varies alot by your right foot. Everyday driving mix of in town and freeway is about 18. I have been getting about 17 lately with the winter fuel. I have gotten as high as 22 one time on a very long trip... all state highways at 60 mph. That trip I drove to destination ( vacation at a lake) - drove around for 5 days (very slow pace) and drove almost all the way home. I thought that my fuel guage must have been wrong and started worrying that I would run out of fuel, so I stopped to fuel up. I had run 863 miles up to that point and had a hard time squeezing in 39 gallons. Keep in mind, for this trip I had the EX all loaded up with the wife, myself, 4 kids, dog and all gear for a week. Also the trip back it was 102 degrees outside, so had the AC on full bore the whole way back (6 hour drive). I have been nothing but impressed by the diesel.

I get alot of looks and questions at the fuel pump when I am filling it up. There are alot of people around where I live that are "green" concious and try to ridicule me on my choice of vehicle (Excursion) saying it is not environmentally friendly. I look at it this way... My wife and I now have 7 kids (oldest is 18). If we were to go anywhere as a family and DIDN'T have the Ex, we would have to take 2 vehicles. Even if both vehicles got 30 miles to the gallon... we would still burn more fuel, create more emissions, than we do with the one Ex.

 

For comparison, I'm at the other end of the spectrum for milleage. I'm a lead foot. I run 75-80 on the freeways with or with out a trailer and as fast as I can get away with around town. Plus, I love to feel the pull as the turbo spools up! I get in the 14's on the freeway. I get 11-12 around town, pulling my Jeep on the flat bed or pulling the small sled trailer. The big sled trailer brings me down to 9-10. My X is 100% stock right now except for the K&N replacement filter.

 

I have found that to be 100% true. With my Ex there is a HUGE difference in mileage on the freeway when you are doing 65-70 vs. 75-80. Same around town. If my wife is driving, she will get about 2mpg less than me She has a leadfoot and likes to show those rice-burners what torque can do. Biggest thing I have found if you want to get better mileage is to try and keep the RPM's at or below 2000. Kindof hard to do that one the freeway, but it isn't too hard if you are driving around town.