have you or a previous owner changed to larger tires with out re programming it in the ECM?even changing the tire 3/4" will cause it to not want to shift into final drive. BUT Maximum MPG is at 2200 rpm
this is just based off my driving with my weight and accessories. also i have the 3.6 with the 6speed. same problem i almost never use 6 gear as i get the same or better mpg with the 300 change between the 5-6 gears. I tended to run about 17-19 mpg at 1800-2K rpms on the highway vs the small hills where as if i leave it in a gear that keeps me at about 2200 rpm i tend to run 19-21 as the engine doesn't have to bog to try and keep the hills. i've also read alot on the 8speed and the manual over the last couple years being paired to the 3.6L it loves the higher rpm ranges. anything under 2100 rpm its a dog. where the power starts to pull good is at 2500 and up almost runs like a two stroke 250 dirt bike. lol i am also on the crap 3.45 gearing that jeep puts in the sports. no clue as to why they didnt do the 3.73 gears on the sports. It would drive so much better with the two trans options in my opinion.
