You may also try a fuel system cleaner like Techron or Berrymans... Could help restore some MPGS, but for the most part the all-time 4wd on the jeep is going to always drain the milage. Thats how it was with the explorer I had before taking my mustang back. Only averaged 14-15 mpg combined, with the 4.6L. The Auto-4wd is horrid on gas