I have a 2dr X and have recently put a 2" superlift on and upgraded to the 17" stock aluminum wheels with the bigger wrangler at tires.32" maybe..? This morning I checked my gas mileage and it's 13.5 mpg I'm getting...that seems really low for a 2dr with only a 2" lift....any ideas on why this is?

Is there anything I can do to improve it?

 

Did you recalibrate the speedo? If this is reading too slow then your MPG will also be reading low. Also if this lift takes the front rake out you will see a slight reduction.

 

what Littlejon said, did you recalibrate your speedo?

 

yup, if you went from stock 16"s with stock tires (I think they measure out right at 29") to stock 17"s with 32" tires and didn't recalibrate your speedo then your odometer is off too so your mpg calculations will be off until you get it recalibrated. Since you went with stock wheels and tires the dealer can do it. Some do it for free and others may charge a fee. Mine did it when I went I went from stock 16" to the 18" sahara rims. At first they tried telling me it couldn't be done, but changed their tune once I told them how (after reading about it on here). they didn't charge me for it. If you change later to anything larger, they will not recalibrate it for you, but there are a few aftermarket options to do that now.

 

I don't have the computer mpg calculator...I figured it myself. I guess it would still screw up if the mile readings are a little off?

No, the rake is still there.

 

That's mixed driving...

 

Without having the speedo recalibrated your basing your calculations on the computer still thinking your running the smaller tire. Your about 11% off with the bigger tires from the old ones. So you are actually at about 15mpg or so.

 

Use your GPS, when you fill your tank reset the trip meter on it. When you fill up again use the reading on your GPS to figuire your mileage.

I went from stock 255's to 295's and 3.21 gears, my mileage is about 18.5 - 20 depending on how much highway I do. It is lower in the winter due to gas mixture and letting it warm up before I drive it. But according to my dash reading I am oly getting 15....so use your GPS, chances are your mileage is still fine.

 

Dealership wants to charge $90 for that.....sounds high to me..

 

I agree that is high. I had it done at McMullen Jeep in Hattiesburg MS and they did it for free. If you are looking at doing bigger tires, gears etc in the future you could get the new AEV calibration tool through northridge. I think it lists in the ball park of $135 which is cheaper than any of the other tools and it does more stuff. Then you wouldn't have to pay again in the future.