'09,f250, 4wd ,sb ,superduty, crew cab , 3.54 ratio?, 285/17's. Hauled cattle for first 3 days and was carefull not to idel too long, just at load or unload point & not for more that 10min. at a time. (Had aready heard the stories and did breeze over the manual before I started.) truck got 4.5-6 mpg!!! dealership reflashed and got some relief but still not better that around 12 mpg but really haven't pulled anything over 10,000 lb. Need reliable info on what pkg's have been tried w\ rewarding results. Is 20mpg a thing of the past?