• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Improving Stock Gas Mileage

ihscoutlover

ihscoutlover

NAXJA Forum User
Location
Edwardsville
I own a '94 XJ 4.0 HO, AW4, with 235/75/15's, what can I do to improve some performace, and pick up some on my gas mileage?? Thanks


Jeff
 
Get a little 4-cyl car?

There is only so much that you can get from a boxy vehicle with a 4L engine... My 95 gets 21 now and that's as good as it's ever been.
 
Bone stock 95 4L/5sp, 206K miles. Most of my driving is highway, usually around 70MPH. I replaced the O2 sensor and gained an extra 30 miles per tank.

scorpio_vette said:
how in the world do you get 21mpg??? my best ever was barely 19, and that was on a 3 hour highway ride with cruise control. around town i was lucky if i got 14, and now i'm down to 12.
Click to expand...
 
Got a roof rack? dump it. Got roof rack rails? dump them (just cover the holes up though). Drive slower when you can (no cruising @ 70). Unload all the extra junk that you carry so that the rig isn't too heavy. Oh and don't forget to wax it every week for better slippage through the air :D
 
You could start with a Tune up (plugs, wires, cap & rotor). Unless it's already been done, drop a new air filter in it ( I don't buy into the K&N drop in's....but several on here do and like them).

I've got a 99 4.0 auto 4x4 and Get roughly 14-15mpg all city. I used to get AT BEST 12, untill I did the above. Also switched to Mobil 1 10W30 Synthetic and noticed about half a mile per gallon increase, as well as a better running engine. Also remember you're in a 2 ton (assuming 4x4) brick with wheels. It's not an escort, and it's not got the handleing of a Ferrari, so don't race the crap out of it. Drive sensable and you'll probably see an incease. I try not to rev it over 2500 when possible.

Couple other things you might consider, I leave my tranny in "3" rather than "D" when I know i'm gonna be under 55 for my trip. And extreme short distance driving is murder on mpg, as well as your engine. Try to avoid it when possible.
 
ihscoutlover said:
I own a '94 XJ 4.0 HO, AW4, with 235/75/15's, what can I do to improve some performace, and pick up some on my gas mileage?? Thanks


Jeff
Click to expand...
First things first, whats your mileage now?
One thing found is during cold weather is getting rid of the K&N cone filter and going back stock box with heat riser will give you 5 mpg back.
 
Last edited:
When I first purchased my 98; I took a trip to the Grand Canyon and received 23-24 mpg during parts of the trip, but that was then.....
Now with all the off road armor and performance modifications... I get 16 hwy on a good day...
MPG/Performance modifications consist of Gale Banks header, Gibson catback exhaust, MSD-6a ignition w/coil, MSD Superconductor 8mm wires, JET Stage II chip, K&N FIPK, TurboCity throttlebody, all synthetic lubricants.....

Charles
 
Man, I get about 16 city with my '89, and thats with a lead foot :).
The '92 also gets around 16 city and the '95 gets around 17 in the city.

The '92 and '95 are bone stock and the '89 has a 2.5" exhaust and a huge K&N conical filter.
 
I cannot believe no one mentioned the contraversial finger nail polish remover :)

Oh and I get 17 on 240,000 miles with 2.5 exhaust and K&N filter only mods. Yea its a brick on wheels and I love it.
 
reddragon72 said:
I cannot believe no one mentioned the contraversial finger nail polish remover :)
Click to expand...

O.K. since you insist... the best thing you can do to improve your mileage is to add acetone to your gas. :roflmao:
BSD
 
My 87 get 18 city 21 hy in the summer and 23 with 1oz of acetone per 10 gal.
Winter drops to 16 city 19 highway acetone don't seem to help mileage in temp below 40.
 
99XJSPORT06 said:
Couple other things you might consider, I leave my tranny in "3" rather than "D" when I know i'm gonna be under 55 for my trip.
Click to expand...
What is your reasoning behind this? You wouldn't limit yourself to the first 3 gears in a stick-shift, would you?
 
otto said:
No, to the first four gears. Overdrive is for sustained highway speeds.
Click to expand...
Yes. However, there's absolutely no reason to put the transmission in "3" unless you need engine braking (or, unless your tranny is borked and shifts in to 4th at the wrong times...)

Normal driving = put it in drive.
 
The acetone thing is interesting. I've never heard of that before. There seems to be some conflicting evidence on the net about it. Many people saying they tried it with better gas mileage as a result.

Lots of other people saying it's hell on plastic and butyl rubber (which I know to be true).

It seems that the key question is this: if you add only 1 oz. per ten gallons of gasoline, that represents less than 1/10th of one percent. Is that a strong enough mixture to do harm? I dunno.

So far, I haven't been able to find any posts of people saying they tried it and had bad results.
 
Last edited:
Weight is a big killer on your mileage. Take out what you really dont need. Always stay on top of your tire air pressures, especially if you live in a very seasonal state like mine. Drive conservatively, find your jeeps sweetspot as far as the rpm's go, for highway driving and stick to it, even if you have to ride the right hand lane. And always keep the engine tuned up well, especially those who have the older models that still have the distributors, spark plug wires and such. I have an '01 so theres not much to change on a tune-up anymore, but I stay on top of all the above mentioned, and I religiously keep a mileage log, and I get an average of 23 mpg.
 
Also verify that the lockup is working on automatic trans. Driving style is what affects mileage the most. O2 sensor should be changed at set intervals, and would affect mileage as the sensor wear.

regards
Torfinn
 
Helium in tires!:thumbup:

Breathe it too right before you drive:confused1
 
You must log in or register to reply here.

Similar threads

blondejoncherokee
Looking for parts for a mostly stock rig
Replies
11
Views
1K
migue978
M
W
Newbie with an XJ
Replies
9
Views
213
Wander Motor
W
R
1992 XJ AW4 doesn't want to shift
2
Replies
20
Views
3K
Rob Mayercik
R
S
another No Bus and faulty instrument cluster thread...
Replies
0
Views
31
stuckinthemidwest
S
W
Replacing & Availability - '92 Manual 5-speed
Replies
14
Views
3K
four_shot
four_shot
Back
Top