Other things can help for increasing mpg, i was getting 11mpg with 33 tires with 3.73 at first after the tire upgrade(saving up for axles and gears). I reset my ecu(so it would start over learning my driving habit), I turn off my Auto overdrive(run about 2500rpm at 65 highway), cause with the low gears, any incline would slow the jeep down and the negine had to work more. I started to use cruise control, changed injectors to Bosch 4-hole design.
After changing the injectors, the engine smoothed out so nicely, it now had a problem staying running it was so smooth. That lead to me finding that my IAC was bad and filthy in the throttle body(replaced & cleaned), guess the old injectors had extra unburnt fuel, it kept it idling and then added new plugs.
After all that i get about 13.75-14.25 mpg now and that is with about 10min idle run time also each day. It small, but still better then 11.
Hopefully when i get the axles and gears, being able to use my overdrive i can keep it about the same or a little bit extra.