New 96 I6 4spd cherokee owner. I actually bought it from state surplus as a fuel saving vehicle. I know, there's one born every day. Figured it would have to do better than pounding my very thirsty pickup over potholed gravel rds. 60 miles each day. So, was wondering if there was a spot here where a newbie could find all the fuel economy ideas that actually work in one place. Like, is there a way to get the auto to stay in overdrive when you drop below 43MPH? Where I drive, if it wouldn't shift down until 35 would probably use a lot less fuel. Mods that have been proven to work? etc. Any suggestions are appreciated.

 

Sure theres stuff.
Run 5W30, run the correct tire pressure..maybe a few lbs more!
Drive unloaded..no extra weight, remove weight..like rear seat if you don't use it..carpet if its nasty! Throw bedliner down if you don't like the bare floor look!! And maintenance, change the plugs & toss in some 703 dodge neon injectors! Run seafoam through her to clean her out!

I'd go through and change plugs, wires if they look bad..if not then they should be fine, I'd change the cap & rotor, fuel filter!!
What tire size is on it? I remember seeing some jeeps having 205's as a factory option, although silly looking it'd give better mileage! If you like the meaty tires, I'd run a 235/75 & no bigger!
You can remove your roof rails for better areodynamics if you don't use them...sure it seems absurd but hey its helping!
Some people are getting like 26mpg on this go green website about hypermileaging! 26mpg in a cherokee is crazy but they are doing it!

I'd take out as much weight as possible, keep her up to date on maintenance, keep the tires inflated, and coast...biggest gas killer is the way you drive! No rabbit starts, & watch ahead. If the light is red get off the gas and coast!

In my 5speed XJ run a 3" lift & 31" AT's & it still has 3.07s..when I swap the 3.55's in it'll probably pick up a little. I get 17-19mpg city depending on how heavy my foot is feeling!..I've gone through and do everything maintenane you could imagine though because the jeep needed it! While doing it I wrapped my header & added a intake heat shield did 703's & a 60mm throttle body. I also plan on a electrical fan swpa here shortly which will deffinetly help in the MPG department!

You can remove the mechanical one which is less drag on the motor, which means more power to do normal driving, which means more efficiency..I'd venture to say if I tryed I could get 20mpg city in a lifted cherokee!

 

You're not gonna change the overdrive function. And besides, there comes a point where lower RPMs don't save fuel because you're loading the engine harder.

Do all the tune-up stuff posted above with high quality parts, clean your throttle body and IAC.

And then live with it. You're not gonna improve it much anyway.

 

I was pleasantly surprised. It looks like the state did a service on it before sending it out. Don't know if that was typical, or I was just lucky. Oil was new with new filter, air cleaner, plugs looked good, all other fluids full, everything working. It was great. So, don't think there are any major service related issues effecting fuel efficiency.
Driving very very conservativly, I'd swear I can see the gas gauge going down. Depressing. Appreciate the ideas so far. The tires are about gone, so will try the 205's. Had wondered about tire options and if they had them listed as possibles once... why not. Does moving the IAT to the airbox improve gas milage, power or both? Love the ideas so far. Any others would be great.

 

It may..i know most people move it to rich it up honestly..but hey if it doesn't work then change it back! You want to add more air to lean it out a bit!
So take the upper section of the air box off...remove the trumpet/baffle..it'll give it some more responce and will allow for more air to more through..in turn it may lean it out just a bit!
Look for exhaust leak! Seafoam that sucker and see if the ehxuast is leaking..if its leaking you'll see smoke coming for somewhere else other than the tailpipe!
Exhaust leak will kill mpg! Cracked header...ect!
Doing the intake manifold heat sheild helped me with mpg..I wrapped my header & did the intake heat shield at the same time and started seeing a steady 1 mpg gain! Nothing else changed! The 703s gave me another 1-2mpg. And I was getting on it more when I installed them and still saw a gain!

 

PUt 205 75 15s on last week and took trip across state this weekend. 1st tank was 22.78 mpg (up from best of 20.84 previous). Average for weekend was 21.89 mpg, with a best of 23.85 mpg. So, pretty excited with the difference of about 1.5 mpg. Next will be the airbox mods.

 

My jeep is stock height and 215/75 tires and gets 26 mpg on the highway but I drive 50-55 usually. I get 24-25 mpg if I drive 60 and any faster than that I don't even want to check haha. A can of fuel system cleaner doesn't hurt every couple of tanks either.

 

I need to try some seafoam or similar no doubt. Put gauge cluster in before the trip last Friday. Was informative to see rpms for each gear and lockup. Was going to try some airflow mods, but drove 60 - 65 against 20 mph headwind for over 180 miles in one segment and still got 19.8MPG. Not so sure airflow mods would help much now. Most of my regular driving is about 45 mpg due to road conditions. Biggest help would probably be to keep it from shifting out of overdrive when have to slow for corners etc. Am going to check out the injectors too and see if they have already been swapped from stock.

 

There is no "similar" to seafoam. There is only seafoam. Seafoam ftw!!!