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bad gas mileage problem

nashman918

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Joined
October 4, 2005
Messages
17
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0
City, State
Corning, NY
Year, Model & Trim Level
99 Explorer Sport
my 94 X with an auto tranny and 121,000 miles is getting very bad gas mileage. When i first bought it at 102,000 miles, i could go about 250 on a full tank, maybe more if i ran it past a quarter tank. now i can only go about 200-210 on a full tank and thats with it almost completely on empty. the following is a list of repairs i've done:

new spark plugs (autolite double-platinums)
new plug wires
fuel pressure regulator
fuel pump
fuel filter
iac valve
195 degree thermostat
air filter
changed oil regularly
egr dpfe sensor
ran seafoam through the engine and fuel system
reset computer
no check engine light - ran self test and came up with no trouble codes
i run 89 or 93 octane and i'm reasonably light on the throttle

I have no clue what to do next. the truck runs good otherwise. I had a 93 xlt with a 5spd that had 210,000 miles. The truck burned a quart of oil every week and i still could go almost 300 miles on a full tank. I just wish i could get that kind of mileage now. The only thing I'm wondering about is that i put a brush guard on a couple months ago and I'm wondering if the added weight on the front end would affect my mileage this much. Also, are there any aftermarket bolt-on parts I can do to improve the mileage. I'm looking into upgrading my exhaust, should i expect any improvements? Any ideas would be greatly appreciated.
 


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Mbrooks420

High Voltage.
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Miles to a tank, and miles to a point of the tank isn't a reliable way to measure mpg. Sometimes fuel gauges lose their acuracy, making miles to a tank pointless. The brush guard shouldn't cause a 40% drop. With the low compression 4.0 I wouldn't bother with the high test gas. A more free flowing exhaust should help a little, and so would synthetic oils in the tranny, notor, and differentials.
 




expl0der8

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Joined
December 31, 2002
Messages
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City, State
Rockford, IL
Year, Model & Trim Level
98 Sport
nashman918 said:
my 94 X with an auto tranny and 121,000 miles is getting very bad gas mileage. When i first bought it at 102,000 miles, i could go about 250 on a full tank, maybe more if i ran it past a quarter tank. now i can only go about 200-210 on a full tank and thats with it almost completely on empty. the following is a list of repairs i've done:

new spark plugs (autolite double-platinums)
new plug wires
fuel pressure regulator
fuel pump
fuel filter
iac valve
195 degree thermostat
air filter
changed oil regularly
egr dpfe sensor
ran seafoam through the engine and fuel system
reset computer
no check engine light - ran self test and came up with no trouble codes
i run 89 or 93 octane and i'm reasonably light on the throttle

I have no clue what to do next. the truck runs good otherwise. I had a 93 xlt with a 5spd that had 210,000 miles. The truck burned a quart of oil every week and i still could go almost 300 miles on a full tank. I just wish i could get that kind of mileage now. The only thing I'm wondering about is that i put a brush guard on a couple months ago and I'm wondering if the added weight on the front end would affect my mileage this much. Also, are there any aftermarket bolt-on parts I can do to improve the mileage. I'm looking into upgrading my exhaust, should i expect any improvements? Any ideas would be greatly appreciated.

I don't see mention of the O2 sensors, those went out on my 98 and the mileage went down the tube. Check those out.
 




Ford_Racing_Guy

Explorer Addict
Joined
September 22, 2003
Messages
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City, State
Spencer, Wisconsin
Year, Model & Trim Level
'92 XLT & '98 XLT AWD
you may wanna switch to running plain 87 octane that your engine was designed to run on.

I noticed that when i started using the 89 with ethanol my gas mileage suffered significantly.

i now use only 87 without ethanol.
 




nashman918

Member
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October 4, 2005
Messages
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City, State
Corning, NY
Year, Model & Trim Level
99 Explorer Sport
thanks everybody for the replies. i just changed the oil with synthetic 10w-30 and filled it with regular 87. we'll see what happens. about the 02 sensors, wouldn't they send a trouble code if they were bad?
 




snoborder42

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Maple Valley/Downtown Seattle, Washington
Year, Model & Trim Level
92 XLT 4x4
The O2 sensors wont necessarily send a code, they only sent a code if something is really wrong. They just get fouled up with carbon and dont work as good as they should.
 




Creager

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Charlotte, NC
Year, Model & Trim Level
'92 Sport 4x4
You need to start setting your trip gauge inbetween fill ups. So that way you know exactly how many miles you are driving. Use the reading on the trip meter to divide how many gallons you have fill up with at the pump (make sure you top it off each time you fill up, otherwise you are going to cheat yourself). That will tell you your miles per gallon.

210miles/17.9gallons =11.73 miles per gallon

Now, if your speedo is off and you are reading less/more miles per hour, it will be inaccurate.

Using 93 is going to be less efficent. I run 89 and get 19 miles per gallon, but i also have 190k miles... running 87 will be the death of my 4.0 (let alone worse gas milage), unless i rebuild it soon.

On your 94, if a O2 sensor goes (as in disconnected or broken, not really gummed up) i garentee it will drop a CEL. But it should not effect gas milage, on my 92 i ran years with a broken O2 sensor (with CEL illuminated), never effected a thing.

A nice intake and exhaust isnt going to change your gas milage much... maybe a half a mile per gallon, per modification? The most dramatic improvment in gas milage I have ever encountered was from re-gearing. But if you are running stock tires, you dont need to waste your time and money.

Of course, you tried cleaning the MAF? i didnt see that listed hehe... that has caused flucuations in gas milage for me before. But never a 40% decrease
 




monkeydude3

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May 8, 2004
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City, State
Millbrook, Illinois
Year, Model & Trim Level
2001 Explorer Sport Trac
yeah... I've learned that higher octane gasoline actually burns a little bit slower to handle higher compression setups (and boosted setups) so when you run that fuel on an engine not designed for it, it ends up guzzling more fuel. So run the regular, and check the 02 sensors. Those do have a huge bearing on your mpg, because they tell the engine to go rich or lean and when... they could be stuck saying rich most of the time....

how hard are you on the throttle? I got under 12mpg when I had a heavy foo ton my 94 XL... when I was light it got better...


George
 




splodo49

Ejection seat man..
Joined
June 17, 2003
Messages
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City, State
Tooele,Utah
Year, Model & Trim Level
94 XLT,75 FJ, 05 Cummins
Ive always got 10 to the gallon... but i have 35s..
 




monkeydude3

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City, State
Millbrook, Illinois
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2001 Explorer Sport Trac
yep.... it's a large cubic inch, lower horsepower engine... which means bad MPG but the reliability on the engines themselves is great :)
 




Mbrooks420

High Voltage.
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I could easily get 17mpg out of my OHV.
 




Creager

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City, State
Charlotte, NC
Year, Model & Trim Level
'92 Sport 4x4
i get atleast 17 mpg 50/50 driving. shoot i get 19 when i dont use the highway much.

12 - 13 when i barrell down the highway at 75mph @ 3000 rpms.
 




darrellx14

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January 27, 2005
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City, State
Leesville, SC
Year, Model & Trim Level
1993 xlt
anywhere from 11-15 w/ 3.27's and 31s and the pedal to the floor just to get to the speed limit
 




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