2010 JKU, 35" Trail grapplers, 3" lift, 4.88's, stick shift.

If I keep it around 55-60, I get around 17.5.
When I'm cruising at highway speed, 65-67 to keep the rpm's up a little, I'll get 15.8 all day long. If I go anywhere near 70, it tanks to 13 or under.

 

2014 2dr 35's with 4.56s, 3" lift. Drove from home to Tulare CA, about 250 miles each way. Avg 19.2 MPG at the pump. Drove between 55-65 mph both directions.

 

2015 3500 miles
305-70-16 General AT2 40psi
Manual
3.73 Gears
70mph 2100 rpms 18.5 mpg
65mph 2000 rpms 19.5 mpg
60mph 1900 rpms 20.5 mpg
MPG measured manually

 

What brand and size tire and wheel are you running? I ask, because I heard that the weight plays a big factor in the mpg. I've had people tell me their mpg actually went up when going from 33's to 35's with 4.10's. They said the 4.10's need the 35's to max the mpg. Anyone else see an increase in mpg when going from 33's to 35's?

 

Running one of the heaviest combos around, 35 Nitto Mud Grapplers on 17 inch Mickey Classic IIIs. I do 16 around town and 17ish on the highway at a moderate speed ( below 70 ). If the temperature outside is in the 30s or below though I can kiss it all goodbye.

That being said, that's on a 14 JKU on stock 3.21s. The Pentastar helps quite a bit and I'm sure the AEV procal fixing my shifting points played a small part as well.