Originally Posted by Goldwing
I keep a maintenance log that includes mileage, computed the old fashioned way (miles driven/gallons). Over 22k miles, mostly highway driving between Holland and Detroit or Midland, I average 27 mpg at 70-80 mph. I once achieved 31 mpg when I drove to Midland at 55-65 mph. Another time, coming back from Detroit with a government car acting as bear-bait, I drove 80-90 (hitting 100+ a couple times) and still got 25-26 mpg. Best on a tank of gas was a little over 400 miles on a round trip to Detroit.
I have the 6-speed, start coasting when a light turns red ahead of me, and generally shift at lower rpms (under 2,500). I have the bad habit of driving fast rather than accelerating fast.
Even around town I get over 20 mpg.
I noticed that you have an Audi A6 in your signature, what kinda mileage do you get in that car? I know it's a lot heavier than the XF.