JfK

Completely stock 2011 Sport with S package, auto trans. I have gotten a lifetime average of 18.XX mpg. My highest tank was 19.5, and my lowest was 17.3.

I achieved my highest tank after a week of ownership, with roughly 700 miles on the jeep. I have not been able to get near that since, most tanks are around 18.4 mpg. My commute is 15 minutes highway and 5 minutes in town. I draft semi trucks and use brakes only when I have to. I try to keep it under 70mph at all times.

bbolander

2012 jku rubi 4:10s and stock 32" tires, 2" mopar lift. got 20 mpg at 70 mph consistently on the highway on a 1000 mile round trip beginning the trip with only 350 miles on the JK. get around 15 in town, 17 mixed.

That's why i'm not going high mods on this one like i did with my 2006 LJ rubi. i lost 3-4 mpg adding the tall lift, big tires, heavy bumpers, winch and skids on it. more interested in mild wheeling today but with a rubi for when i need it.

it's the big tires, lift, heavy stuff and speed that drops the mpg big time.

catahoula

Same setup here. I have 3.73 gears. When on Hwy I use cruise and set in Economy mode. Also to add I did buy for the gas mileage. I bought it for the fun.

cody6597

I just returned from a 1200 mile round trip to Kansas from S. Texas. My set up is a 12 unlimited rubi with 4.10's, 35 mtrs and lift with 4400 miles. I tried to keep the RPMs around 2100 on highway driving and I manually figured between 17 and 18 mpg. The other thing that helped was turning off the ESP. I seemed to gain about 1 to 2 mpg by doing that. I will post an update once I get the procal installed this weekend. I also had my wife, kid, dog and a loaded back end. I dont care if I get 12mpg...wouldnt trade this thing for any other vehicle out there.

viking

Well I don't care if it is a 2012 or a earlier JK. When you go 70 mph this flying brick will get just that poor gas mileage. There is no aerodynamics at all. It is meant to cruise along doors off going the speed limit, off roading. I don't think there is anything you can do to this brick to get real good gas mileage. Maybe a diesel but a hemi would only want you too push it like a race car using gas. It is just a fact.

Shoup

I was disappointed in my mpg as well, then I remembered I didn't buy a prius.

trippnk

For the guy who said milage staying the same regardless of speed made no sense, I did the math and there was less than 1mpg difference between 45mph all city stop and go as 71ish all Highway! I'm also making an appointment at the dealer to have the transmission checked as it seems to slip alot, and even more when it's cold. I doubt they find anything but it's really bothering me.

iphonedylan

Without putting a whole lot of thought into and a guy who put 15k miles on a 2011 JKU in 6 months driving 90% highway, you're best mileage is when you Jeep makes that final shift into overdrive. Get it into that final cruising gear and keep the RPMs as low as possible. It's not fun but if I had nothing to do, was ahead of schedule and had a full line up of Sirius NFL network I'd keep it around 60-67. I couldn't use cruise because on moderate hills in middle TN it would hunt gears so I had to give a few MPH to keep it in overdrive now and again but I imagine the 2012's are better about this. 140 miles a day is expensive unless you're in a compact or on 2 wheels. I also put 5k on a HD Dyna in those 6 months and a couple thousand on my wife's Mercedes but premium fuel in a sports car is actually more expensive than my Jeep. After you leave stock tires forget about it without regearing. I find it's less taxing mentally to just leave the dash computer on cardinal direction and temp instead of the estimated fuel economy...

m998dna

Slip? ... you can always install a Paramount Performance Valve Body. For sure it will stop slipping... google it. Bill even beefs up transfer cases and sells high stall converters for SRT8's.. probably can whip one for your JK and make that thing sing.

> or wait until Diablo Predator comes out with a tune for the 3.6L / W5A580 5-speed combo. There's a tuner by the name of Johan that will wake all this up and make that tranny shift like it's supposed to...

> and even possibly change the shift points like he does on the LX SRT8 cars... however this may not be possible on the JKU due to 4-wheel drive - but you never know.

I think it's just a matter of time when the 2012 Jeep will reap the benefits from 5 years of aftermarket engineering for the Jeep SRT8... I'm especially interested in what Diablo has in the works, if anything.

Good luck at the dealer...

trippnk

By slip I mean froma stop I will push the gas, the engine will rev "a lot some times", then it will accelerate. It does it driving to if I try to quickly accelerate, hit the gas and it seems to stumble a bit searching for a gear then go.

Anyone running 285's with an auto, what are your rpm's look like on the highway?