Reread post 21. I was specific about the Smarty tuner beta program 4.4 on level 3. I had it downloaded for a couple of years and then had to get my ecm reflashed and ran it without for a couple of months. Then reloaded to level three of the 4.4 beta and picked up fuel mileage again. All mileage is figured miles/gallons pumped, the overhead is off a couple. In addition to that on level three, the truck runs like it should have off the showroom.

 

Just returned from a trip with my '03, averaged 19.7 mpg. Running 70-75 mph with a few stops along the way for the girls. SMARTY set to level 7.

MikeyB