so i drive a 2007 unlimited and my gas milage sucks!! i have 35s on a 4 inch lift. im getting about 9 miles on the highway. i have the stock 4:10s and nothing under the hood. what should i do? regear to what size? dont want to have to get rid of it but im filling up every 2 to 3 days!!

 

Best bet would be to look for lighter 35" tires, or go smaller on the tires (if you can handle your jeep looking like a roller skate).

A programer like Superchips with economy mode will help a bit.

A cold air intake could help along with a cat back exhaust.

Without lighter tires or driving habit change the other mods will only get you maybe 2 to 3 mpg better. However their cost is a lot more than the fuel savings.

Bigger gears are ok (5.13 for an auto or 4.88 for a stick with 35s is about the consensus). But if you have a heavy foot that won't help and could make it worse since you will be running at a higher rpm with the bigger gears.

 

Something doesn't add up there. I have heavy 35" KM2s on my JKU Rubi w/ 6 speed and get 18MPG on the highway. How fast do you drive on the highway? What transmission?

Erratic driving will drastically reduce fuel mileage too.

If your setup is similar to mine, you have to either be driving like a maniac or have something wrong with your Jeep.

 

so what are the lightest tires like could u give me some options? i have pro comp extreme ATs 35x13.50.

 

its automatic. but i have to step on it on the highway or else ill be going like 30 i have to really push it to where my rpms are like 3.5 the whole time. and im always on the highway

 

How are you calculating your MPG? Unless you have reset your senors with a programmer the computer will be off with the bigger tries.

 

To determine RPMs with gears use the chart from the faq part of the Modifed section.

So if you think larger gears are going to help you on the freeway plug in you actual tire size with your desired gears and it shows your RPMs at 70mph.

I have found it is accurate with my setup.

 

You're doing something wrong if your getting 9mpg on highway...

Don't drive like an asshole and turn your overdrive off.

 

I don't get why you would be staying at 3500 rpm with my 35 I can run 70 all day long and typically I am only around 2100 rpm and I have the stock 4:10 gears in mine. The only thing I have done for performance is the CAI and it didn't make that much of a difference.

 

well then idk i dont drive like an asshole or nothing so i guess ill just figure it out at the local 4wheelparts