I have a stock 1999 XJ auto, with roof rack. Just got it, so I haven't done the mileage yet.

 

Hey Springfield! I bought my (turns out badly pitted), windshield there at American Auto Wreckers. Use to kill days there at that little bar where the Hwy splits while my mom was at Sacred Hart.

With 703's in my stock 90 I got her down to 10 knocking around (was 14). Got 18-19 on the trip picking them up (300 miles each way). Got 17 on the one short hwy trip I've made with them in. Still working it out. Could maybe be Renix needs an adjustable MAP to deal with the higher flow rate, but really, I don't know. I will try to "reset the renix ECU" ??? don't think it resets.

 

4.5in lift, 31's,3.55 gears, 4.0, 4x4 and auto 96 Country. Just had it on the highway and got 7MPG's. My Jeep sucks for MPG but is BA offroad.

 

something is wrong there. thats horrible.

mine: 3.5" lift, tire in the roofrack, 30x950's, 3.55, auto, getting 17 around town.

 

x2. Knowing next to nothing regarding a 4 1/2 inch lift with 31's don't know what to say. Check the MAP tube to the TB. Maybe it's hooked to the turbo!

 

Everything is new. Cat-back, cat, every sensor on the entire Jeep, fuel pump and tank, filters, plugs, wires, coil, injectors and evap. As far as I know it should be at optimal performance.

 

Stock '00 4x4 with 784 injectors, i'm getting less than 15mpg average during my weekly commute... but a mostly-highway trip recently, I got 21mpg.

 

I have a 2000 Sport 4WD four door and during the summer I consistently get 15-16.5 in a very hilly city, and... well, highway varies. If it's 55mph highway, I do 60mph and get 22. Doing 70mph I get 20, and doing 75mph I get 18.

 

I took an average across my last 3 fill ups and I got just over 20, on my 2000 Sport 4x4...now that is majority HWY driving too.

 

not to thread jack, but have you also compensated for the extra distance with the bigger tires? and how heavy is your foot?

 

I'm getting 13-14 mpg with my 4.7 stroker being broken in. Just a little over 1,000 miles on the rebuild. 96, 3 1/2 lift, 32x11 BFG's, 3.55 rear, auto. I like the increase in power and hope the mpg's continue to rise.

 

OK 1999 XJ Sport, totally stock, 4.0 Engine, Auto Tranny, 4WD. Just filled tank and calculated mileage. Not over 65 mph, mostly city driving, 19.39 MPG!!!! All of this without a tune up!!. (Tune up is coming, 42, XXX Miles)

 

Joe came to me with:
Throttle Body Spacer, Pro Performance Stage 1 chip, worn out NP231, 215/75/15 Courser AT's (27.7 inches), AW4 Tranny, 3.55 gears, 127K on original motor:
11mpg city, 19 mpg highway

I added Neon 703 injectors, 235/75/15 Micheline LTX-MS2's (28.9 inches), "newsed" NP242, 137K on original motor:
12.9mpg city, 21 mpg highway

The bigger, grippier tires make it less skiddy and I've become less prone to playing around trying to make them bark. That's probably making more of a mileage impact than anything. I had a 3.07 rear in for a couple of months and I got 24 mpg! I also couldn't tell how fast I was driving, the cruise couldn't hold any speed and my AW4 tranny was shifting all over the place trying to work it out. Still, 24mpg!

 

I'm 39 with a family not 16 with a death wish. I drive very sensibly and I get my average from filling the tank and then refilling it to figure mileage and it comes down to 7MPG's. Thats why I bought 2 other Jeeps so I don't have to drive it. My ZJ and TJ gets 13 and 11 and thet are bone stock.

 

X2. Someone needs to learn how to do math...