Mileage

[1994xlt]

What size and brand tires?

Tires can cause a significant lose in gas mileage, not by size, but by weight.


I get 19mpg on the highway in my 04 with 5 speed and 3.0 but only 14-15mpg in town because of traffic.


i run michelin defenders in the stock size 235. I tried some cool lo9king tires that were 30s and my mileage dropped about 3 mpg. You didn't norice any driving change but wow, the gas mileage changed. I took them off after one tank of gas.

Stock size like you but has some cheap Lexiani tires that were on it when I got it

 

[lil_Blue_Ford]

Tires alone shouldn’t cause a 10 mpg condition unless you’re trying to turn huge tires with not enough gear.

I’m running 35x12.50-15 mud tires at 12 psi on my Choptop with a 4.0 OHV, FM-146, 1350m and 4.10 gears. With a bad computer and possibly bad O2 sensor I was getting 12 mpg. Fixing those jumped me to 15-18 mpg. Then I added an electric fan which may give me another slight bump.

 

[lil_Blue_Ford]

Also, I’ll throw this out there, the A4LD slushbox isn’t helping anything with mileage. My 92 jumped from 12 mpg to 14+ mpg by doing a tune-up, oxygen sensor, and some valve body work including a TransGo shift kit and adjusting the bands. I was going to investigate the computer condition when someone decided to hit me.

 

[gaz]

@1994xlt
Great, you have established that your power plant is the Federal version; you can expect 17 city/19 highway with the automatic in the optimum stock alignment

What is/are "you butchers"???

 

[1994xlt]

@1994xlt
Great, you have established that your power plant is the Federal version; you can expect 17 city/19 highway with the automatic in the optimum stock alignment

What is/are "you butchers"???

Typo

 

[1994xlt]

Okay so I guess with all that said we’re do I go next. Some have said check Ecm

 

[lil_Blue_Ford]

Okay so I guess with all that said we’re do I go next. Some have said check Ecm

All of the sensors can be checked with a multi meter, there are specific resistance and voltage tests for each.

The ECU is either in the cowl in the engine bay or is in the passenger side kick panel area. I’m not really sure which location for the 3rd gen. I’m working on a video about the ECU in my Choptop that was bad.

 

[1994xlt]

All of the sensors can be checked with a multi meter, there are specific resistance and voltage tests for each.

The ECU is either in the cowl in the engine bay or is in the passenger side kick panel area. I’m not really sure which location for the 3rd gen. I’m working on a video about the ECU in my Choptop that was bad.

Ok thank you

 

[gaz]

@1994xlt
You need to determine why it is stalling.

 

[1994xlt]

@1994xlt
You need to determine why it is stalling.

Hoping the vacuum leak is the reason, I do need to replace my fuel tank filler neck line has some cracks in it maybe that why it’s doing it?

 

[Shran]

I get 12-14 around town in the winter and maybe a little over 15 in the summer. 1994 super cab, 4.0, automatic, 4x4.

10mpg is pretty low. Keep in mind idle time in the morning = 0mpg. If you idle for 10 minutes five days a week and only take short drives, it may never reach operating temp where it gets its best mileage. Idle time is cumulative as well, say you idled for 70 minutes during one tank of gas - that's 70 miles you could have driven at highway speed. The math on that might look like 10mpg x 15 gallons = 150 miles but if you didn't idle at all and drove highway speed, you might go another 70 miles on the same amount of fuel - so 220 miles ÷ 15 gallons = 14.67mpg. Fairly substantial difference.

Not sure what else to suggest other than maybe cleaning the MAF sensor. It always seems to be really dirty on vehicles that I get in and I've seen it cause really weird hesitation and rough idle issues. Oiled aftermarket air filters compound that problem - oil mist will hopelessly contaminate a MAF. A good paper air filter that is clean will be plenty.

The plastic tube that goes from the air filter box to the throttle body is cracked on a lot of these trucks too, if you have a lot of air bypassing the MAF, you will see weird symptoms.

 

[1994xlt]

Okay thank you for your reply

 

[1994xlt]

I get 12-14 around town in the winter and maybe a little over 15 in the summer. 1994 super cab, 4.0, automatic, 4x4.

10mpg is pretty low. Keep in mind idle time in the morning = 0mpg. If you idle for 10 minutes five days a week and only take short drives, it may never reach operating temp where it gets its best mileage. Idle time is cumulative as well, say you idled for 70 minutes during one tank of gas - that's 70 miles you could have driven at highway speed. The math on that might look like 10mpg x 15 gallons = 150 miles but if you didn't idle at all and drove highway speed, you might go another 70 miles on the same amount of fuel - so 220 miles ÷ 15 gallons = 14.67mpg. Fairly substantial difference.

Not sure what else to suggest other than maybe cleaning the MAF sensor. It always seems to be really dirty on vehicles that I get in and I've seen it cause really weird hesitation and rough idle issues. Oiled aftermarket air filters compound that problem - oil mist will hopelessly contaminate a MAF. A good paper air filter that is clean will be plenty.

The plastic tube that goes from the air filter box to the throttle body is cracked on a lot of these trucks too, if you have a lot of air bypassing the MAF, you will see weird symptoms.

I have cleaned the Maf sensor, because I was having an issue were one day I left my house and my truck just stalled out and died and I would start it up and it would just die again, so I cleaned it and the engine light went away but if I’m driving and it seems to be when I’m driving a constant speed for a while it will turn on and then go back off again and stuff but if I take a certain road and take that certain road back to were I came from that light will turn on at roughly the same spot every time

 

[Shran]

Find out what code it's throwing. In my experience the check engine light going on and off usually indicates a misfire. That could be a bad plug/wire/coil pack, cracked head leaking a little coolant in and fouling the plug, carbon fouling on the piston, insufficient/too much fuel pressure, other things probably.

Coolant temp sensors going bad used to be a problem, it would tell the computer a wildly inaccurate temperature and they would run really rich or really lean

Back in the day fuel pressure regulator failures were really common too and that would cause noticeable changes in fuel mileage

Not telling you to replace any parts, just do some testing.

 

[1994xlt]

Getting it tested or checked at work today I work at a ford dealer I’m hoping the starz taster or wtv it’s called can see a memory of check engine light so it doesent have to be on for it to pop on