bad mileage

[deerslayer5253]

i have a 2001 f250 with the 7.3 and at best i always got 13 mpg i tried one of the superchip milage chips and it didnt really change it is there anything i can do to get better milage the tires are good so i cant think of anything else thanks for the help

[Fred Swanson]

Exhaust, intake...if you haven't done those already...

[deerslayer5253]

i forgot to say i have a 4 inch exhaust and a k&n intake

[jesilvas]

Dually? Lift. Tires. What gears?
How do you drive it?
If it's nothing insane, then you've got issues to fix. Boost leaks. Exhaust leaks. Seized caliper slide pins.

[deerslayer5253]

its not a dually and the lift and tires are stock and it has 3.73 gears

[jesilvas]

Yea you got issues.

[audiocontr]

Originally Posted by jesilvas

Yea you got issues.

Helpful


There are several of us that have mileage close to yours and no idea why. I've scanned my vehicle and tweaked everything I know how. No change. Let us know if you figure it out.

I'm leaning towards injector issues on my personal truck

[jesilvas]

Originally Posted by audiocontr

Helpful


There are several of us that have mileage close to yours and no idea why. I've scanned my vehicle and tweaked everything I know how. No change. Let us know if you figure it out.

I'm leaning towards injector issues on my personal truck

Well, it's true I mean, if my dually with fuel tank, tool box, fifth wheel and gooseneck hitch and rails, and 318k miles on original injectors gets about 16mpgs then there's something going on.
But I understand and have read those threads where people have changed all kinds of things and are still having problems. Heck, it might be something in the trans that is offering too much friction and therefore creating the loss of mpgs.

[audiocontr]

We are very aware that something is going on.


It is: Those who report the same issue of around 12mpgs seem to be automatic 4x4s. Manuals and 4x2 do not have the problem.

Its not:
Transmission. I'm on my second as of 4 months ago and no change. As others who use the 44 have no problem, it eliminates the transmission as a potential.
Driving habits: Mileage difference between driving hard vs granny is MAYBE 1 mpg difference and that could easily be explained by not filling the tank all the way at refuel.
Winter fuel: Problems there in the summer, winter fuel knocks a bit off as it does for everyone.
Fuel pressure/blocked lines/filters: I just went through replacing everything on fuel delivery. I have perfect pressure and no issues. Mileage is still crappy
Up Pipes: Replaced. No change in mileage
Boost leaks: Have none. Fully inspected with a boost leak detector
I have NO codes
I have NO hanging calipers

Things that dont help:
I have some beefy tires. Let me rephrase, i regret purchasing big beefy tires. They are loud and reduced mileage instantly. I've compensated my mileage expectations and even adjusted, i find my truck is low on MPGs
The Tuner - I have the same one as you - Super Chip or whatever they call the silly thing. It makes a large difference with the truck - no question about it but it does NOT increase fuel mileage. It decreases it if anything. I get better in stock tune. There is no tuner out there that increases fuel mileage. I repeat - NO tune will increase mpgs. (There are some really informative posts about the aerodynamics of the 7.3l trucks and ways to get 20+ mpg. Tuner packs were tested and none increased mileage over stock. The research is there on this one - please spend some time reading)
I have a sneaky suspicion that 4" turbo back exhausts and TYMAR intakes also decrease mileage. This one usually causes a riot though
on the forums


At this point im leaning towards bad o-rings on injectors. I'm saving some cash for a stage 1 swap and i will see if it increases mileage more than the normal 1-2 mpgs.

[mxfever090]

^^^^ What size tires?