According to the Ultra Gauge Mounted on the dash, my 01XJ with 3 inch lift and 31" tires is getting me 14.8mpg right now. In the summertime, it would get 15.2. This is just driving back and forth 11 miles to work each way, not much highway. Both my cats are bad and the CEL will come on about once a week due to that. I clear the CEL with the gauge whenever it comes on.
I drove to Boston last year and reset the average MPG on the gauge, and on the highway I got 19mpg while driving between 60-70MPH. The gauge helps you improve your MPG by showing you instant MPG as well. You see the number going down? Let off the gas a little.
It plugs right into the OBD2 port. http://www.ultra-gauge.com/ultragauge/
33s on 3.55 buddys Why going to 4.56s though, jumping to 35s?
When the 33's wear out it'll be going to 35's. And living in the moutains and wheeling with lots of ledges to bump up. The extra deep gearing is always a plus since the Xj usually only gets driven when it's on the way to the trails
the xj i just got rid of was gettin about 12 in town with 31's. my 95 with a 4 cyl would regularly get me 20-22 in town, back roads, uphill or mudholes. the best i got off of it was 25 driving through small towns. i would say i drive like an old lady, but my mom only gets about 16-18 on the same roads. guess who has the lead foot
89 with 4.5 in lift and 4.56 gears with 33x12.5 and I get some where around 15 in town and a solid 24 MPG hwy 2x4; in 4x4 its a bit lower. She use to get better stock, I use to be able to go from Missoula MT to just out side Seattle WA of 1 tank and after 10 trips doing that had a HWY average of 26.5 mpg.
1989 XJ, 5spd, np231 with bjconversion SYE , re3.5, 33x12.5r15 BFgoodrich ATS, D30 F, Dana 44 from 87 with 4.56s, Custom front bumper.
94 yj: stock everything and 4 angry squarrels under the hood.
2001 4.0 aw4 I drive 150 miles freeway each way to work (once per week) and I'm 90% freeway all the time at 72 mph indicated on my factory speedometer. 30" tires on 3" lift with full skid plates and sliders. No roof rack or heavy cargo. I calculate my mileage per gallon using my odometer for mileage and number of gallons of gas at each fill up. I average 18.8 mpg with this setup. I'd like to do better (since I see that others do). At 72 mph I'm at 2500 rpm indicated, I've read that around 2100-2250 is optimum rpm for this motor's fuel consumption.
I'm considering 31" tires to reach that rpm at my current speed, but am pretty sure if I simply slow down 5 mph I'll find what I'm looking for but be 5 minutes late for work every day.