I just bought a 2011 f250 supercab with a 6.7l. Great truck, I have about 1000 miles on it and log all of the fuel, My first drive i averaged 23mpg, since then it has dropped to 18, the transmission seems to be shifting differently than it did earlier seems to shift slowly 2,3,4, any ideas would be appreciated Thanks,

 

Haha I got the same exact thing on mine. Drive home got the best mpg I'd seen sonar after that I average about 17 with mostly city driving and 19.5 when I had all highway. I don't really have shift issues except when it's cold it's a bit sluggish. Don't worry the mpg you are seeing are typical. You may not have the latest tranny flash or it could just be cold. I have 4500 on mine now. Enjoy the truck I was t laughing at you either just the fact that these trucks must be programmed to get better mpg the first tank n

 

Your mpg is typical. I see 15-17 around town, 19.5-21 empty highway and 11-12.5 towing. Your tranny may still be "learning" your driving style. As you get more mileage on the truck, the tranny will smooth out. There have been a few who have been complaining about shift flares and erratic shifting. There is a TSB out to fix tha issue. I am still on the "factory" calibration and haven't had a shift issue in 8600 miles.

Good luck and enjoy your truck. I do every time I get in it! Still smiling...

Dave

 

15-16 in the city, 23-24 on the highway and 12-13 towing my 30' Warrior.

 

Your 1st Tank of fuel mileage better. yep. Your starting out with a totaly clean DPF. then the regens start.Mpg drop.