You have to remember that gearing and frontal area are the biggest reasons why jeeps don't get decent mileage. In a Maverick that is more stream-lined a properly tuned injected 6 cyl. would give good mileage and performance.
Hmmm sounds like you had highway gears and that crappy automatic that sucks the life out of every motor it gets stuck behind. Because every TJ I have driven with a 4.0 and the six speed ran great. I got a MPI fuel injected 4.2 in my CJ-7 with a 4.0 head conversion and an Ax 15 transmission. Throwing away that train wreck of a 2V carter (and i like carter carbs) was the best thing I ever did for that jeep. With the same 3.31 gears I went from 12 MPG to an average of 18 MPG and I dont have to downshift to 3rd going up hills anymore like I use to have to with the carb and the T5(yes the gear ratios are similar between the two transmissions OD is the biggest difference). The biggest thing is It was 6 degrees outside this morning, I can walk outside and turn the key and it will be running within 5 seconds, if I still had the garbage carburetor on it then it probably would have taken me the better part of 20 min to get it so it would not bog out and stall because it was too dang cold. Oh and to darren I did all the wiring on the harness and everything myself mopar didnt come out with that MPI unit for the 4.2s untill a couple months after I did mine. (and yes I can get you pictures to prove that the motor is injected it if you really want me too lol)
I love my 4.0 jeep! 19 mpg with plenty of power. I'd like one in a Mav. Bet it would get 25 mpg......
That's what made me start thinking EFI in the first place. It gets cold out here and it's a real uphill battle to turn the engine over.
I've had more luck in cold weather with carbs. The secret is an EFI cam with a wide LSA, a smallish sized carb and a good electronic igniton system. With these three, no choke is required for starts down to 20*F. With a choke and an open exhaust crossover in the intake, 6* shouldn't be a problem
