Hi all. I have a 99 F250 super duty crew cab 4x4, V8 5.4, auto,3.73 rear axle with 35000 miles.

I can't get the @#$%^& thing to run any better than 9 or 10 miles to the gallon. I was able to run 17 miles / gal only a couple times last summer, but nothing like it anymore. I also tow a trailer: Max load 3000 #. Gas mileage when towing: 7 to 8.5 Miles / gallon !!!

Took the truck to 2 different dealership and nobody can find anything wrong. The only glitch that was found was a faulty pressure regulator; but that didn't help much.

What kind of gas mileage do you guys run on similar trucks ?
I'm trying to collect enough data from different owners to prove something's wrong with my rig.

Any information will be greatly appreciated.

thanks.

 

First, I would question your 17mpg number. I doubt that your truck configuration is capable of that.. You have what I would call a 'heavier' configuration, CC, auto, 4x4.

Folks with this configuration are generally in the 11 to 13mpg range with mixed city/highway driving and an occasional 15 or possibly a 16 if doing all highway with a tailwind.

The 17 you quote is likely because you didn't get the tank as full as the prior tank.. This is easy to have happen as even slight difference in the truck angle when filling it up can make a few GALLONS difference on fillup.. Averaging total miles/total gallons over several tanks overcomes this 'fillup' error..

Ok, the fact still is though, you USED to get better mileage than you are now..
In the winter months it is often the case that mpg will drop by as much as 2mpg or so.. Reasons for this slight drop include:
- Many states run oxygenated (sp) fuel in the winter months which is not as efficient. (it evaporates easier I think).
- Folks tend idle the trucks longer at startup waiting for the cab to warm up
- cooler air is more dense, thus slightly more fuel is needed to keep the same optimal fuel/air mixture.. (The computer compensates for this automatically).

So this 'might' explain why your not getting 12mpg in your normal everyday driving.. But where is your 13 to 15mpg when doing highway only??

-Do you have a brake dragging?
-Is there carbon buildup? (try running a techron additive for a tank, I hear this really works to remove carbon)
-Did you try resetting the computer? This will affect driving for the next few hundred miles while the computer re-learns your driving habits.
(unplug the battery while turning on the lights for 5 or 10 minutes to reset.
-Are you letting your wife drive the truck? (doh, I didn't say that).

FYI, I have what I call a 'lighter' configuration
5.4L 4x2 5sp 4.10LS
My average in mixed city/highway driving is 15.5mpg.
My all time high is 17.4 doing mostly highway driving. (btw, I filled up at the same station/same pump on this tank).


>Hi all. I have a 99
>F250 super duty crew cab
>4x4, V8 5.4, auto,3.73 rear
>axle with 35000 miles.
>
>I can't get the @#$%^& thing
>to run any better than
>9 or 10 miles to
>the gallon. I was able
>to run 17 miles /
>gal only a couple times
>last summer, but nothing like
>it anymore. I also tow
>a trailer: Max load 3000
>#. Gas mileage when towing:
>7 to 8.5 Miles /
>gallon !!!
>
>Took the truck to 2 different
>dealership and nobody can find
>anything wrong. The only glitch
>that was found was a
>faulty pressure regulator; but that
>didn't help much.
>
>What kind of gas mileage do
>you guys run on similar
>trucks ?
>I'm trying to collect enough data
>from different owners to prove
>something's wrong with my rig.
>
>
>Any information will be greatly appreciated.
>
>
>thanks.

 

Have you tried switching brands of gasoline? I found that I get an average of 2 mpg better by using Citgo or Coastal as compared to Mobil in the same octane.

My 5-month average was 11.3 mpg using Mobil gas from the same pump almost every time. Since I switched brands of gas its 13.4 mpg. Not a bad increase, and cheaper prices too.

Sam
1999 F-250 SC, SWB, 4x4, V10, Auto, 3.73

 

You didn't put on different tires/wheels since you first recorded your milage?

 

Well, I can't speak for the heaviness or lightness of the vehicle having anything to do with the gas mileage that you are seeing. I have '99 F-250 CrewCab 5.4L V-8 3.73 4x2 and I average anywhere between 15.6 and 17.4. This is on an engine that will soon be replaced for the piston slap problem.

I will also agree that the brand of gas you use will affect gas mileage. I seem to get better mileage using Amoco, Citgo or Quick Trip (QT), than I do with Texaco or Mobil. Around here, Atlanta, QT and Citgo tend to have the lower prices.

IMHO and experience from other friends, 4x4s tend to get lower mileage that their 4x2 counterparts.

 

My truck v-10 5 spd 4.30 Lim Slip 4x4 usaully gets around 10 this is wether empty or pulling 6000 Pd car trailer or 1800 boat or hauling 1500 camper in bed or camper = car trailer or boat. since i put tonnuo cover on now it is about 11-12 empty 4 weeks ago took car trailer 400 miles to pick up car cold and rainy day got 6mpg worst i ever got. think it was s**ty gas cause tank coming back was around 9

 

Well guys i now have 10,400 miles on my 2000 f-250sd, 4x4, 5.4L s/c longbed, 5sp 410 gears, and my mileage has gotten worse now.. I used to see alot of 14's like you've probably seen on my other postings, but now all i ever see is 12 to 13, and sometimes 11's too.......! Is it those arabs and their high priced deluted gas? Or is it just me...? I still drive the same, still use the same gas(texaco)... Its got me puzzled, but if really cared i would have gotten a toyota, I love my super duty, even when gas is a buck sixty five a gallon....!
J.R.'s Lake Fork Guide Service, Alba, Tx.

 

MRBASS
I am soon to recieve my truck and after reading your post it sounds like we will have almost the same truck I opted to stay with the short bed. So besides the gas mileage how does the truck perform with the 5.4L 5sp 4.10LS. Have you done any mods yet? The anticipation is killing me!!!
Rob

 

I have a 99SD 250 5.4 auto trans. 4.10 rears large tire option from Ford with aluminum wheels. Long bed with fiberglass cap.
I average 16.3 in winter 16.4 in summertime on Highway. City I don't care about. It is not a city mileage vehicle.

 

just wanted to let you know that my F250 SD 4x4 xtra-cab 32,000 miles original tires an I order her brand new, at this moment has not ever done better than 10.5 mpg ever average is 9.8.

currently have chipped it and put in flowmaster muffler hopefully it will go up a bit but not anticipating this to happen.

I also snow plow with her and my mpg goes down to the mid 5's then.

don't feel alone and if there is a miracle cure for bad gas mileage that you come across I would be interested to here it

happy gas guzzzziling
jeciv

 

I agree with jeciv, if there is a miracle cure for the gas guzzling bring it on and pass it out. Don't feel like your alone with these trucks getting bad gas mile. #'s. Since new i've gotten 10-10 1/2 mpg, with an all time high of 11 1/2mpg. I have a 2001 250 SD SC SB 4x4 w/4:10's an auto w/265-75-16 tires. Runs good, plenty of power, not 1 single problem yet(knock on wood)and I just love this truck. I ussually use Phillips 66 gas cause it is convienient, tried Casey's 1 day, DON'T, gas mpg went in the crapper, est. 6 mpg. I wish I had gotten the overhead consol.

 

Is there any way to get the overhead console if your truck doesn't have one now? I know you can get just a aftermarket one, but can you do the gas mileage on those? Just curious.

-Jeff
'00 250 SC SD SB 4x4 5.4L

 

Jeff,

Check with your local Ford dealership parts counter and see if it is an item that you can order. I always get the F-Series Accessories catalog and the overhead colsole is not listed there for purchase. I think it is standard on the Lariat model only. I have not seen the mileage computer in any after market overhead console.

Steve R
'99 F250 4x2 CC LWB 5.4L 3.73

 

I also run Citgo gas instead of Mobil. Seems like Mobil bogs the truck down and Citgo is cheaper anyway. Is there anything to that or is it just in my mind? Anyone know the differences between the companies?

 

I have 99 SD F250 5.4 4:10 Larait .I have never get less the 10.5 the most i got was 15 mpg .that is with the trip computor.