More MPG for a Jeep?

Is there any way to actually get more miles per gallon than just not being hard on the pedal?

Iam asumming you have a 4.0 with a a auto trans. My best millage is 18 to 20 on the highway. Mine is pretty much stock. Ive had increases on other vechiles by adding headers, cam change and perfomance exhaust usually about 4 to 6 mi increase. Havent got around to adding mods to my XJ yet. You might want to try a cat back an air intake if you dont want to go with the headers.

1996 4.0L High Output, auto trans, w/Select Trac (RWD&4WD).

And what's a "cat back" btw?

Depends on what you're getting now. My mileage on my '88 (4.0L, auto, 2wd) with 155K is about 19mpg highway and 15ish city. If I "heavy foot" it around the city, it drops to 13ish.

The intake and exhaust systems are pretty restrictive. Replacing them with unit that allow more airflow always helps. The "cat back" Cam refers to is an exhaust system from the cat converter back.

I have a K&N filter mounted in the stock box. It seems to help throttle response but doesn't seem to help mileage much.

I just found out from a friend who works at a car dealership that taking a CC off of a vehicle that's made any time after the 80's is bad if you don't know what you're doing. He says that taking it off would screw up the on-board computer and make it unstable.

I did see a few converters and they all have a O2 sensor bolt on the side of it, so it would probably screw up the computer.

A Cat Back is a performance Exhaust from the Catalytic Converter Back. No it is not a good Idea to remove the catalytic converter.

Modern converters aren't as restrictive as the cats produced in the 80's. Unless your'e runnig a bad ass cam or high compression pistons (which would confuse your puter anyway),you are better off leaving the cat alone.

I think all jeep owners have been searching for this and the answer is yes. You can use a less restrictive exhaust and intake (search flowmaster or K&N air filters). Some camshafts (search Crane Camshafts) will improve gas mileage and roller rockers will free up your valves. You can try giving it more spark(search MSD). But after you spent thousands of dollars to gain 5 MPG, how many miles would you hafto drive to get your money back? After you drove that many miles and you have recovered your investment to save money on gas, how much is your "Frankenstine XJ" worth. I love my Jeep and don't ever plan to sell it, so who gives a flying f#*%!

I'm quickly coming to think the same as you, XJasper. When I first got my XJ, I completely freaked at the low miles. It motivated me to change the fuel filter, plugs, wires, etc., good things to do and I did gain mpg.

To improve air flow, I pulled the stock air box out and where it used to have about a 2" by 3" inlet hole, I opened it up (with a jig saw) to almost the size of the end of the box, then put it back in. I'm now looking at opening up the flat spot in the exhaust right below the header if possible. May add a high flow cat-back... Just trying to eliminate one restriction after another as I can.

I've seen bored out throttle bodies, there are cold air intakes from a dozen makers, fancy plugs, wires and coils, I even saw an electric supercharger on ebay.

While I was on my quest for more mpg's, I was at NAPA buying the fuel filter when the guy asked what I was up to. His suggestion for getting better mpg out of a Cherokee was to quit checking my mileage or sell the Jeep. I suddenly realized, I could spend a lot of dough trying to squeeze a few more mpg out of an engine that really doesn't seem designed for mpg.

I've decided, adding or changing these different things all have pro's and con's, most probably will gain you either power or mileage, some just make you feel like you've made your ride look or sound a little better.