Only getting 12mpg

07wranglerX

New member
I recently bought an 07 wrangler X it has kelly 315/70r17 tires with 4.10 gears, 6sp 3.8 v6 it also has a 4" lift

I usually shift around 2500 rpms, on the highway i stay around 65mph. Reading a lot of other forums, similar vehichles are geting 16-18 mpgs. I am only getting around 12 mpg mostly highway.

Advice?
 
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I don't think the x was ever offered with 4.10's and that could be your problem. Do you need to downshift a lot on the highway to keep your speed up, especially on hills?


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Is your speedo correctly calibrated for the tire size?

I'm not sure if it has been calibrated or not. I bought the jeep a few weeks ago from dealer. I thought that it had to be calibrated for the dealer to sell it. When i can get the money im probably going to invest in a superchips flashpaq to check.
 
I'm not sure if it has been calibrated or not. I bought the jeep a few weeks ago from dealer. I thought that it had to be calibrated for the dealer to sell it. When i can get the money im probably going to invest in a superchips flashpaq to check.

We'll if it's not calibrated then that is your issue.
 
I don't think the x was ever offered with 4.10's and that could be your problem. Do you need to downshift a lot on the highway to keep your speed up, especially on hills?


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The 07 wrangler X did offer the 4.10s and the dana 44 axle with the tow package, which i have. I havent noticed that it really struggling with maintaining speed. 6th gear doesnt have a lot of get up and go but i pretty much only use it for cruising at a set speed anyway.
 
That's about how much I was getting when I threw on the 35's before the recalibration on my 07 x with 4.10's (auto) now I get around 16 highway
 
That's about how much I was getting when I threw on the 35's before the recalibration on my 07 x with 4.10's (auto) now I get around 16 highway

It was my understanding that the recalibration works a lot better for the auto because it resets the shift points. having the 6sp would the recalibration affect it much?
 
It was my understanding that the recalibration works a lot better for the auto because it resets the shift points. having the 6sp would the recalibration affect it much?

It will fix your computer to recognize that you have the larger tires now so your speedo and mpg computer are calculated correctly.



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Diablo Sport Trinity if you plan to later install Ripp manifolds or supercharger, you won't have to replace the tuner down the road.


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The 07 wrangler X did offer the 4.10s and the dana 44 axle with the tow package, which i have. I havent noticed that it really struggling with maintaining speed. 6th gear doesnt have a lot of get up and go but i pretty much only use it for cruising at a set speed anyway.

Huh, interesting. Thats a great option to have.
 
It does just reset the mpg on your dash, because that's always just an approximation. If you have bigger tires it takes longer for 1 full rotation of the tire meaning you're mileage is more than your dash actually says, so if it says you're getting 260 or so per tank of gas, your really getting 300 or so which is obviously going to help your mileage calculation if your calculating every time you fill up rather than just looking at the dash. I've had 37s for 2 years and haven't re-calibrated I reaaaally need to get a superchips
 
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