it seems i can get better milage if i keep rpm from 1500-2000 , i just traveled from london ky. to houghten mi.,, fuel milage got real bad [8-9] just after mackinaw bridge going there ,,on the way back i tryed keeping rpm's at 1500-2000 using man mode or going 65-70 and got 12-14 mpg's,on the way there i noticed rpm's at 1100-1300 do to only going 45-55 mph [wind and traffic] try this and see if it helps you too,it apears lbz's don't like to be lugged,thats why these trucks like to run fast on the open road [ till mpg's drop off at over 2200 rpm]