i have never seen my gas mileage go above 17.1 mpg even on the highway. is something wrong. 2008 x stock wheels and tires. i've seen posts of 21 to 22mpg on the highway. wtf.

 

How fast are you normally driving on the highway? That makes a big difference.

Mike

 

What size are your tires and what is your axle ratio? I have 32" tires and 3.73 axle ratio and typically get 17 in the city and have gotten up to 23MPG on long highway trips. It took a couple hundred miles to get above 20MPG however. Also, if you hold in the button when the computer is showing MPG it will reset the MPG calculations and start over. If you reset the MPG before a trip on the freeway you could see the highway numbers faster.

 

Are you looking at the displayed mpg?
Believe only your own calculations at each fill-up.

 

I'll bet that you didn't reset the mileage computer before you hit the highway. The computer calculates average MPG from the time is was last reset. If it hasn't been reset in a while, you would have to drive a gozillion highway miles to shift the average up to the low 20s.

Next time you roll onto a highway, push the button under the tach and hold it in until the mileage computer resets.

Verify your mileage by filling up before and after your highway trip.

I have a 2008 X 2dr. I recently drove from eastern Long Island to the Poconos and averaged 22.97 mpg for the trip there and 23.21 for the trip back. That included slower driving (with some stops) on PA route 209 and averaging 70 mph for much of the balance. This included driving through the high hills and small mountains in NW Jersey and NE PA. On flat highways at 65 mph, I can get between 24.6 and 25.3 mpg (headwind vs tailwind). Use cruise control for best mileage.

My regards,

Widewing

 

X2 on all of this, also your acceleration has a lot to do with it. If you like to get up to speed real fast, that will suck the life out og your MPG's. Your MPG's during Fast acceleration will be less than 5, so to compensate you need to go a long time at 20-23 mpg to get above 17. Take it easy and don't worry if people pass you, your in a Jeep not a Mustang.

 

Mine gets 16.0 ... seen as high as 17. Hand calc. I don't expect to get anything over 18.

 

I don't worry about mileage in a Jeep. If you are, trade it for a Toyota.

 

My gas mileage on my stock 6spd rubi:
16mpg dash
15mpg calculated
100miles/day 80-90mph
the days where traffic is at a steady 60, the max mpg i can obtain is 18 from the dash so prob 17 actual. i've noticed when you detatch the bat and reset the comp the dash will display 18 to start but slowly works it's way back down to 16.

 

also how many miles are on your Jeep? Others have posted that MPG climbs after the 6000 mile mark