ahhh. it was just an expression. a brick is a brick. you can make it an ugly brick, but it's still going to have the driveability of...



A BRICK. just do what you're going to do and if you end up with anything substantial let me know and I'll definitely do the same upgrades
but I think you're just going to be gaining imaginary MPG's here until you get those 4.10's in

 

oh and please keep your wipers on. I hope you were kidding about that
just get fully tuned up, fix leaks, keep the engine clean, and seafoam it and drive it nicely until you get gears

 

Dude ur dreaming. I'm sorry but u wont get in the 20s lol. And if its auto the best thing u can do is get gears. I always tell people time after time don't buy a car that u can't afford to drive. Its that simple. I'm not trying to b mean here but u shouldn't have lifted it and what not if its a highway rig that doesn't see offroad too much. And if it is offroad a lot... well no offense man but that's the price you pay for a wheeler. Ur just gonna have to suck it up or buy a commuter. Its an old inline 4.0 wasn't made for gas mileage. It was made to last and pull its wieght. Its factory rated at 18 tops. So trust me ull never be seeing 20 lol. If someone on here gets more then 18 id love to know how.

 

I've seen so many gimicks and tricks over the years, I don't know which ones are legit and which ones aren't.

The vortex generator sounds interesting and I know they use them on airplane wings for improved aerodynamics but, I just don't see them doing much for a square box driving down the road at the posted speed limit.

 

I do know that cruise control kills my mileage. I live in Northeast Georgia, so it's very hilly. If I drive with my cruise on the stinking thing keeps kicking into a lower gear to keep the speed up on EVERY hill. Last night I took a trip and noticed my avg eco dropped to 13.8 with cruise. On the way home I left it alone (no reset), but didn't use the cruise and bumped up to 14.3.

 

I get 19.8mpg average and on the flat at 55mph 33mpg!. Thats a UK gallon which is more but its not bad, however we pay the equivalent to $9/Uk gal for petrol. Most Jeeps here are Diesel and average 30mpg.

There are many LPG Jeeps here too, that is approx half the price of petrol but it cost about £1000 to convert, and you don't get the same mileage/litre.
I was thinking the same as a previous post on this thread in having 2 cylinders shut down when not needed. I noticed my computer was telling only 88mpg at 60mph in neutral going down hill, that's bad and it means the engine is using a lot of fuel just ticking over.
But like someone said before these are not good on fuel but they are cheap to buy here, and easy to work on, parts are cheap but most of all , they are pretty cool and retro.

 

I have a 98 with 4.0, AW4, 3.55 gears, 2" lift, Surco rack, and 235/75-15 tires (29 inch). I get about mid 14 around town, and just a couple of weekends ago I took a 110 mile trip with the cruise set at 65, me, my wife, and our 140 pound mastiff in the XJ, the air on full blast in near 100 degree heat, towing a 5'x10' single axle trailer with 250 pounds worth of stuff in it. I got 18.2 MPG on that run, based on mileage and gallons used off a full tank.

Getting in the 20's is possible for some folks with stockers and good driving habits. Flat terrain also helps, which we have plenty of in Texas.

 

Idk if I trust that. That seems a bit far fetched.

 

Mine is a 'Stock as a Rock' 99' 2 door Sport. I too have the AW4 with 3.55 gears. She pushing 258K but runs like a top. On my 1000 mile round trip in May, I got a total of 23+ miles to the gallon averaged over the entire trip, and that was going over a few mountain ranges here in Nor Cal. I went the speed limit or slower, keeping in mind my limited funds for gas, thus really keeping my foot out of it. Since I had just got the Jeep, I wasn't sure what to expect in MPGs. I was pleasantly surprized at what I got.
On my last trip about 3 hours north and back this last weekend, I wasn't 'trying' to conserve, and I got 20.4 miles per gallon. I just found the "Fill Your Tank" calculator a few days ago near my "Garage" here on the site, and logged my lastest trip there. I will start using that on a regular basis. Kinda cool.
I don't have any CC, lift, lights, bumpers, racks...nothing = Less drag. I'm running some Cooper Trendsetters I got from a guy here on the forum.
I have to say, I've had a change of mind where modifying this vehicle is concerned. I am so happy with the way it is, I don't want to mess with perfection. I still wheel it a Hollister Hills, tho perhaps a bit less radical then some...
I have come to the conclusion I will buy another Cherokee to Mod.

 

I went on a trip to Oklahoma, a little over 900 miles from where I am at.
All stock, 3.55 gears on an AW4, while towing my 300 pound motorcycle on the back and I averaged 18.3 MPG going 65 most of the way with A/C on max.. I hit hills halfway there.

 

A product that I've been using for yrs in every XJ I've owned, in fact, everything gas powered I own, is the Fitch Fuel Catalyst.
I get good returns with it, usually a 1.5-3 MPG increase depending on conditions. Example: When the '99 was aquired a month ago, she was doing about 21.5 on the freeway at 65-70mph without. Since the install, I've been getting an upwards of 24.5-25, a tad less if the A/C is running. It's bone stock running 235/70-16 Yokohamas. My 325k mile '97 still gives me almost 21 running 65 mph and it has A/T tires on it.

People been telling me for yrs I'm full of it, but the Jeeps, my CR500's, snowmobiles, pontoon boat, chainsaws, leaf blower, weed whip say "Thank you babe". An added benefit, I never put Sta-Bil in nothing anymore, fuel stays fresh for a very long time. Still running my yard equipment on 2 yrs ago gas(of course, stored in a metal can, it cant stop the lighter hydrocarbons from breathing thru plastic), they always start easily and run like I just got the fuel at the servo today.

 

Trust it. Don't trust it. Believe it, or don't believe it. It's true either way, and I have no reason to BS anyone.

I grew up under the hoods of cars,and have owned 4 Jeeps, as well as many other cars. Also, I currently work in IT, which mean I'm working with numbers and calculations on a regular basis. Dividing miles driven by number of gallons used is something I can do in my sleep. It's third grade math. I even used the exact same fuel pump at the station for my initial fill and refill after the trip to get my gallons used.

Keep in mind that there were some changes between 1988 (yours) and 1998 (mine) that resulted in improved fuel economy.

 

Over 5 tanks I have averaged 19.23 gallons. All stock, AW4, Shell 93 octane and synthetic in everything.

 

Just by driving like. Old lady around town an on the highway I reached around 18-20mpg it all went south though tonight I was about 40miles away from home and I went the 65mph speed limit. But going there I went 10 Under the whole way. Also I managed to not block any traffic the whole way.

 

I read somewhere, (The manual i think) you should use only regular unleaded gas. The L6 is designed for a lower octane......bet your mileage would improve a bit if you used Regular instead. That's all I use. Not to mention it's cheaper.