Loss of highway mpg

[demontang]

I checked it on a few ranks and the tune mog if off by 0-.2mpg on average. My last three intown tanks where 13.3, 14.1, and 13.9 with morning warm up for 5-10min. My last three highway where 7.7,5.7 and 6.5 it's terrible. I can hook up my 6000lb trailer and do better in town then my unloaded highway. I have had a dealer look it over and they found no codes etc either. They thought the mileage is reversed cause they don't hear of 14 in town. I'm about to cut my loss and move on to a different rig. I was getting better mpg with 37" tires and 3" of lift cause I averaged 16mpg highway over the mountain pass and down to oregon.