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Poor gas mileage.

Easy Rider

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October 5, 1999
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I have a 91 Explorer with 180,000 miles on it and recently I am getting very poor gas mileage. I used to get about 310 miles per tank(20 gallons). Now on a good week I get about 260 miles per tank. Any suggestions?

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Try the following:
1.Clean MAS
2.Clean throttle body(use oxygen sensor safe cleaner)
3.Restore Engine Retorer (oil additive-improve compression)
4.Fuel injector cleaner
5.New air filter
6.Fuel filter
7.New plugs
8.New wires
*Don't fforget to re-set your computer.

[This message has been edited by S.Matsushige (edited 10-14-1999).]

Hey S.Matsushige

how do you reset you computer and what does that do to the engine??

i also get not so good gas mileage. 1991 with 140,000 mi i average about 270-300 on a 20 gal tank. i have done everything you listed except clean the throttle body. not so sure where it is and how to clean it. in addition to what you listed, i have k&n drp in filter,holes in air box but i do run 30x9.50's on 15" wheels. oh yeah, i have one of those air tornado systems too, what a waste of $.


shawna l.

To reset your computer, just disconnect your battery for about 5 minutes, then reconnect. This basically causes the computer to forget its old settings and to re-learn your engine. This allows any mods or improvements you've made to the engine to be able to be recognized by the computer and used to their full advantage. You may run rough for a couple of days while the computer learns, but after it does, you'll notice the difference.


You guys think you have it bad?
My 93 XLT is getting approx 200-220 miles to a full tank, maybe 240 if I do straight highway driving. I have the K&N drop in filter.....going to put some hoels in the box asap....I just got some Jacobs wires and Bosch Platinum +4 's , I hope to god this fixes the problem......
keep your fingers crossed!



I think it's important to note that getting around 300 miles on a 20 gallon tank equals about 15 miles per gallon. With combination driving (city/highway) on an engine that is more or less adequately maintained isn't really bad at all, considering the rating for automatic V6 explorers is around 16mpg city. Remember, you're tooling around a multi-ton vehicle that is about as aerodynamic as a loaf of bread.

Especially if you have a lot of miles on the motor (which will become less efficient over time and wear no matter what you do), a decrease of 2-3 mpg over the life of the engine is (I believe) to be expected.

After all the fixes that S.Matsushige has suggested (not too sure about that 'engine restorer' stuff, anyone have input on that?), which should mostly be taken care of with scheduled maintenance, the next important question is this: How do you drive? Do you jack-rabbit off the redlight? do you pass other cars on the freeway a lot? Are you an impatient driver? Do you sit in stop-and-go traffic a lot? All these things will impact your mileage as much, if not more than the other factors.

My two cents Dead Link Removed
95 explorer

Another thing to take into consideration is tire size as well. Most posters notice a drop in mileage as the tire size goes up. This is due to the larger diameter of the tire and the speedometer and odometer not being calibrated to the increase in tire size. You may actually be getting the same or better mileage but it doesn't show. For example while originally running 235s I was getting about 350 to a fill up or 3/4 tank. Going to 30s my mileage went to 325 or so. Now with 31s I get 300 or so. As Scott mentioned alot will depend on driving habits. I do mostly highway driving. Also since I do it so early in the morning, I don't run my air in the morning and only need it in the afternoon. As for the throttle body and the MAS, if you unhook the air intake hose from the airbox to the top of the engine, it'll expose the Mas at the airbox end and the throttle body on the engine end. MAS can be removed for cleaning. Clean the throttle body with a carb or throttle body cleaner that is oxygen sensor safe. Shawna, I would remove the Tornado. I think it only restricts the air from getting to your engine. I do have a K&N dropin filter with hole in the airbox and I removed the screen from the MAS unit as well. Hopes this helps.

A couple of points. One, Engine Restore and all other miracle fixes do not work. At all. They gum up the passages and can actually cause premature engine failure. Second, have any of you replaced the O2 sensor? The first sign of an O2 going bad, is worse gas mileage. O2's are only good for about 75,000 miles (give or take). This is not just my opinion...... my significant other owns an Auto Repair shop.