All 09 trucks have MDS.Can't tell when its on or off.Works smooth.Its turns 4 cyls OFF every chance it gets.My MPG info I reset when I left the dealer with only 30 miles on the truck.Drove 50 miles home on interstate and two lane with a few miles of side roads.Showed about 19.2 when I got to my driveway! I have the 3.92 rear gear with 20 inch tire/wheel package.Turns the effective rear gear to 3.71.