Fuel Mileage

[Don Harper]

I have just bought a 2004 F-350 Super Duty dullie with a 6.0L diesel with 64,000 miles. One reason i bought it was fuel mileage. Well so far it has not gotten any better mileage than my 1995 F-350 dullie with a 460. My first tank of fuel i got 9.2 miles per gallon . so i was told to use an additive that might help .So i used an additive made by Ford for 6.0L and it has pick up to 13 miles per gallon. So what im wondering if 13 is about average or do you think the truck should get better mileage, if so where would I look first. One other thing i am concerned about is the air box . It looks to me that it is restricting air flow. Would i be wise to go to an aftermarket air box and filter?

[merlin5577]

Are the numbers your posting empty or towing?

A cold air kit will help, but you'll get better results with an exhaust.

[Don Harper]

Thanks for commenting! The numbers I posted was running empty.

[merlin5577]

That is low for running empty. I have a few friends with trucks like yours and they get 15-16mpg empty.

The first thing I would do is make sure the truck is in a good state of tune. Change all the fluids and filters, make sure the tire pressures are correct, etc... If you havent already done this you will probably pick up a good amount of your lost mileage.

Is your check engine light on by chance?

[Don Harper]

Was serviced at dealership when I first bought the truck....has had good maintenance records. Engine light is not on. Going to try changing muffler and pipe per my muffler man. If I end up changing the air box I will have to change the whole thing I have found out....cannot just change to different filter like K&N. I'll keep researching what else I can do.