F-250 Diesel Fuel Mileage Issues - Need Feedback?

The oil companies have change to the low sulfer fuel and its effecting the mileage I went thu it try running a bottle of marvel mystery oil when filling up and see if that change the mileage.

Some people are running snowmachine two cycle oil and its working for them.

Another problem which you may see is small fuel leaks which there is not much you can do about it, the new fuel is thinner and in some of the older engines it a real issue.

On the brighter side come winter it will start alot easeir and the is no more winter fuel, I had no problem last winter here in Alaska.

Ok other than the programmer (those things can screw up systems too... had too many programmers and chips cost their owners money on a p-stroke due to this).. are their any other mods to the truck at all? Most love to get the custom exhaust that's why I'm asking.

I would have asked if it was after a visit to the dealer if not using a programmer as Ford had many weird recalls for the 6.0s dealing with the idle on those trucks... and most involved reprogramming 3 modules (remember your power programmer only fools the truck).... Possibly the reprogram did something.. may be wise to see if the program has changed again from your Ford guys and run the latest for a while and see...

Other than that, Have to see the truck to get more ideas... Don't normally do P-stroke work, but those two are the things we see a lot of .....

Temperature, grade of diesel fuel, how you calculated the mileage that you were getting in the beginning are all going to change fuel economy. It is true the the truck does not have any fuel economy rating because it is over 8500 GVW.

I would check your economy after your next oil change and have put 1000 miles on the new oil. Try to drive the same way you always do and monitor the mileage.

13 mpg doesn't sound that bad for a 250 SD

I wouldn't use after market chips....very bad for your truck. Your fuel mileage will vary until your motor is worn in (around 150,000 miles). Mine is just below that and the more I drive it the better my fuel mileage has been getting. Also are you doing a lot of short trips? That will really kill Fuel mileage on a diesel. Have you been keeping your oil changes and filters clean and up to date? That will also effect your fuel mileage. Watch the fuel you are putting into your truck as well. Some stations use bio-mixes which don't get as good of fuel mileage.

F250 Diesel Mpg

As with all diesels, its all about the fuel. Any variation in fuel composition or quality can have an effect on the fuel economy. However, I agree with the opinion that mileage can vary in a vehicle that isn't "worn in".

I agree with Jim W, its the new Bio-Diesel. If something, like your turbocharger was messing up, the diagnostic report on your computer would have poped up the "Service Engine Soon" light. All Fords are computerized man.

Don't know a lot about the problem but I would check the fuel filter, check for possible leaks, and see if the fuel has changed ie; cheaper grade different mixture and soforth. Have your driving habits changed?

You mat have a leaking injector that allows a bit too much fuel on each stroke or a leak in the fuel supply system.

Do you know if the turbocharger is functioning correctly?

Check out your air filter, oil, and transmission fluid as well.