Before i bought my xj i was talking with a guy i believe his jeep now has 6.5 lift with 35's and he was saying he gets around 17mpgs but prior to the lift he was getting 22mpg high way. Does the seem possible, is there any mods that will help improve gas mile per gallon?

I'm gettin around 19 to 20 with 5 in lift 33s make sure you r geard right for tire size good exh and header.

2" BB and 235/75 wrangler dura tracks- 18mpg is usually what i can get.. on pavement. off road it can be as low as 14ish.
BUT, i think ive still got a PCM issue that results in slightly lower mpg's. best ever was about 20mpg's. and 300 miles on odometer before low gas light kicked on. but ususally 250 before low gas light.
the PCM thing results in it not giving acurate reading of throttle position. replaced everything else, and issue has all but disappeared when i replaced fuel pump/filter assembly as there was all sorts of **** in there that didnt belong: leaves, tons of sand and an old gasket probably belonged to old pump... ugh...

I'm sitting at stock height with 235/75 big foot at and getting about 20mpg highway. I'll be putting on a,2" lift soon with same tires. I don't expect mileage to change.

Bigger lift means bigger tires. Bigger tires throw off the Speedometer & the Odometer. If the speedo has been regeared you still need to confirm actual mileage since the gearing is never perfect. Until you know that the vehicles odometer reads correctly, talking about MPG on a modified Jeep is apples to oranges.
just my .o2

Mine is dead on on the speedo I can drive past one of the cop things on the side of the road and it reads the same as my speedo I get around 280 to 290 miles on a full tank of gas when the light comes on I havnt noticed much of a change at all from bone stock 355 gears to 5in lift and 33s with 410s

i need headers cuz mine are cracked so im sure that has an effect on my mpgs. but no one knows tricks to boost up mpg

just from being on here ive gathered 703 or 784 injectors, bored throttle body, intake and exhaust along with better plugs wires and rotor cap and properly inflated tires help the most. Oh and keep your foot off the skinny pedal lol Oh and a seafoam treatment seems to have help a bunch of people too. And I know its gonna start a war but my throttle body spacer gained me 2 mpg other people are gonna talk **** about them but it helped me. Just my $.02 from what ive gathered reading threads

Agreed. Bigger tires makes speedo read slower, therefore less miles, resulting in worse gas mileage calculations. Which is probably why so many people notice such a drastic drop in gas mileage when going to a larger tire. My speedo is 5-10mph slow so I never even bothered calculating my gas mileage. All I know is bad.

I drive my jeep everyday and wheel it on the weekends I know from stock to what I've got now I'm still using the same amount of gas a week to work and back the biggest thing I think that helps is I keep the mantince up 33s at 35psi good exh and header the only place that I know ive lost mpg is on the interstate maybe the gears have caused that

The spare tire was on top of my XJ and when it was removed the XJ seemed to gain around 3mpg. A lifted rig is going to increase air resistance some and mpg will drop as a result. But, it's not a massive drop unless something else is wrong. My '98 XJ is on 33s with a corrected speedo. I check mileage every tank and it gets right around 16 mpg in varied driving with an average use of throttle.
my .o2, DougN