Had a TJ back in high school that I never modified. Just bought my first 2016 2dr JK sport automatic and had a 2.5" Teraflex lift and 35" tires put on last week. Yesterday I took it on the interstate for the first time and got a little nervous. Knew my gas mileage was gonna suffer, but I was going 70mph on my speedometer and passing people....that's not normal. Also, my steering felt a little slippery.
A friend of a friend mentioned his lifted 4dr JK getting 22mpg. What?!?
Here's my Q's:
How do I go about correcting my speedometer?
Will the steering settle over time?
And whatever that guy did to his 4dr...can I do that to an automatic 2dr?!?

Note: Still a newbie, so my knowledge of "jeep jargon" is limited.

 

To correct speedometer you'll need either PROCAL or FLASHCAL. You'll put diameter of your tires and it'll adjust your speedometer.

When I hear people getting 22 mpg driving a wrangler a specially lifted with larger tires, I just ignore it!! I get 16 mpg on a good day with 2.5" lift, 35" tires 3.6 engine, with auto transmission.

There are plenty of threads on mpg, check them out!

 

Here is the MPG you can expect from a basically stock JKU. Anyone claiming repeatable 22mpg is lying or ill-informed. Maybe they never corrected speedo. I check every single tank using hand calculations. Here is the data.

 

C'mon now! Those are the same guys that get 28 mpg in their Cummins pulling 45K lbs off the bumper hitch.

 

I just upgraded to 35's 2.5 lift kit and I'm averaging 17.5mpg, 22mpg? When I was stock I was barely getting 19.

 

Rofl, I wish I got 17 miles to the gallon.
But I also am geared at 4:88 and should be running 37's

 

There are a variety of programmers that can take care of the speedometer. Until you correct that, not only will the speedometer be wrong, but so will everything calculated off mileage, including your odometers, MPG readout, and distance to empty. I don't believe any two programmers offer the same features, so check a variety out and see if there are any that offer any features you'd really like that aren't offered on another. And ignore all MPG, horsepower and torque braggadocio: You're not going to get anything seat of the pants.

As for the flighty steering, you have a caster problem caused by the lift. There are several ways to correct. The most basic are camber bolts. Do not do! While a cheap way for cars to fix, they can loosen up from the vibrations a typical off-roader goes through. There are new, fixed length front lower control arms. These will better set your caster for your lift, but they are not adjustable if you want a different caster for whatever reason. Then there are control arm geometry correction brackets. Ditto the problem with not being adjustable. They also hang down a little bit, so might be subject to damage. They also take a smidgen off of articulation. Finally, there are adjustable front lower control arms. This is the ideal solution, but also the most expensive. And you'll need to get them properly aligned. It can be done in the driveway, and that's how I handle my own, but you may prefer to pay a competent shop to take care of it for you. Some control arm brands are adjustable without disconnecting one end, which must be super convenient. I don't have that, so it's a minor pain to adjust mine. But, once set they're good to go for a long time.

Hope that helps and welcome back to Jeep!

 

3.73 gearing at the moment. 4.88 in the near future. So I'm guessing my mpg's might drop a bit.

Sent from my iPhone using JK-Forum

 

I'm running 35s and a 2.5 teraflex kit as well. The steering was a little bouncy so I lowered my air to around 37 psi. Drives nice, but down to about 14.5 mpg (city and highway driving)

 

37 psi is still too much. Chaulk rest will show 28-30 is sweet spot for 35s