worst case for my 99 ZJ 4.0 11100 miles stock is in the snow, at 4 mpg city. in the summer on the freeway i get up to 22 mpg. but thats on a good drive 200 miles+. but there are many factors involved in the gas mileage of a vehicle. rings plugs valves gear ratios timing tires torque converter in autos. the list it huge. the only thing i can really tel you to try is to try and keep it around 1750 rpm freeway. the least amount of pedal is best. i can get from 10 worst to 18 mpg best on a 10 mile freeway trip. depending completly on how i drive. but if that dosent give you noticeable mileage increase then i say you should check some of the stuff i listed.

This is very inteteresting, my 06 Rubicon that has only been getting about 12 mpg just broke doawn and it was the fuel pump. Only 9K miles and just went from driving ok to nothing and they said they replaced the fuel pump. I'm beginning to think there's a bad supplier out there. I'll let everyone know my mpg after a full tank.

Wolfy You can't trust them dealers! As good as vehicles are now the dealers have little to do.. so they makeup things that pay them the most. I think the intank pumps are longer lasting then the older diaphram types.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

I have a 03 Rubi with some extras Jeeperman Rock sliders, Big Daddy front rock bumper and the rear thanks to the girlfriend it was a gift for quiting smoking. I am guessing I have added around 800 pounds of steel.

I have be tracking very close my gas millage this month.

229 driving as mild as I can I shifted every time the shift light went one. I drove 3 miles an hour below the speed limit. Talk about boring.

<img src="/forums/images/graemlins/frown.gif" alt="" />

212 driving like I stole it 90% of the time.

Honest this thing just sucks on gas mpg <img src="/forums/images/graemlins/butwiggle.gif" alt="" />

New fuel pump, installed under warrenty. Runs the same as before and last tank was 13.2 mpg driving it back and forth to work.

Bumped my tire pressure up from 35 psi to 50 psi (max printed on sidewall is 55psi).

Milage went up from 12 MPG to 17MPG and that included a day of wheeling off road and crossing a 3,500 ft mountain pass.

Bit rougher but worth the gas savings.
I have to assume flat highway would be a bit better.

I'm at a 1/4 tank and 305 miles on the 18 gallons I put in before we left for the weekend.

Of course the last 1/4 tank in these XJ's only lasts about 20 miles! <img src="/forums/images/graemlins/lol.gif" alt="" />