$hitty gas mileage. Need Help

[Jeepenstevo]

1059303

I have a 1990 Yj with a 4.2L In 6. Im running 33s with stock gears. (3.76) Right now im getting about 10 miles a gallon. Which really sucks. I am missing some vacume lines but this weekend im going to put all new vacume lines on. I also put a new carb on it and opened up all the air ways. Flowmaster, new cat., airintake. Does anyone no what to do to recive better gas mileage? Any help would be nice. I have a friend that gets 15 miles a gallon and he is running the same set up i am. The only diffrence is that he has 4.11 gears. If any has any ideas about how to retreave better gas mileage it would help me greatly with gas going at $1.50 now. [addsig]

 

[gonzo891]

1059307

plugs, wires,egr valve pcv& pcv breather. change all the oils grease up the wheel bearings. is a 258 don't expect to get the same gas milage as a rice burner[addsig]

 

[jeepster]

1059375

try adjusting your air fuel mixture. also check what air pressures your running at. hope this helps[addsig]

 

[pinaplebob]

1059382

I wish I could get a gallon of gas for $1.50 it's around a $1.80 here[addsig]

 

[Jeepenstevo]

1059438

what do u mean ajusting the air fule mixture? How do i do that? Would vacume lines help?[addsig]

 

[Bounty__Hunter]

1059443

Do you have the auto or manual transmission?

3.76 gears never came in a Jeep. 3.73 did, close but not the same. 3.07 is the most common with the 4.2L and 5spd, not sure on the autos.

You'll need to regear to compensate for the heavier larger tires, that will help out the mileage, as the engine is struggling in too low of an rpm to move the rubber.[addsig]

 

[bluebelle]

1059498

Regarding your interest in increasing your mileage - if the only siginficant difference that your friend's jeep has is the 411's, then you may want to consider the way you drive yours. I just bought and rebuilt mine (92YJ/6cyl/man) and haven't even used a tank of gas yet. But. . . I can tell that the mileage is about what I used to get in my 67 Galaxie 500 with a big block - about what you get = 10 mpg.

I haven't been able to determine what exactly is the problem with mine. The entire machine is rebuilt except the short block, which behaves well. My thinking is that these little beasts are very temperamental to the way they are handled. I'm real heavy on the throttle and love to go real fast, so perhaps my shitty mileage is because all I do is keep the throttle down.

There're some things that you can try with yours that I'm going to try with mine.

1. Be real careful with the throttle.
2. Start slow off the line from a full stop.
3. Install a vacuum gauge and try to keep the manifold vacuum as high as possible.
4. Keep the tires inflated to 36 psi.- bumpy as hell, but will save gas.
5. Don't lug the engine - keep it spinning but not too high.
6. Install an electric fan. I'm installing a Black Max 2200 cfm electric rather than stock.
7. Keep the oil a 50:50 synthetic blend always one quart low to reduce drag on the crank.
8. Install a Jacobs’s ignition kit.
9. Ensure your allignment is perfect.
10. Pray.

I'd be interested if any of these suggestions work for you. Let me know and I'll keep you posted on my efforts.
[addsig]