Last time my fuel mileage went south was due to a front brake caliper dragging. It didn't feel like it was dragging or pulling. The fuel mileage simply dropped like a rock. The only reason I discovered the problem was I felt heat as I passed that wheel. When I jacked up that wheel, I couldn't spin it by hand. Did a front end brake job on the truck, and the fuel mileage went back up.

 

I just encountered the same problem on my 2006. The high pressure pump had to be replaced after 30,000 miles. since then my MPG droped like a rock, from 15 to 11 highway. I changed all the filters (air, fuel, oil) and still no luck. The work was done by the dealer, could something have happened at the dealer that would make the milage go south? Could use all the feed back I can get.

thanks

Andy

 

Any mods? Are you running a tuner?

 

I bet that ever last truck is still getting better economy then was listed on the window sticker

 

I have never seen a window sticker on a superduty with the milage estimate.What is listed in your part of the world?

 

its not listed FORD has never made a claim what it is.. All the stickers are blank.

 

If I am not mistaken 3/4 trucks on up any MFG. does not show MPG's. You probably will not find them in the EPA MPG listings either.

 

I am running with no mods or nothing yet. The truck has 35000 miles on it. Haven't had a chance to do any mods. Can you reconmend what mods I should under take for better MPG.

 

Just thought, but if you are living in a cold region it might be the fuel. They may be switching to the winter fuel which will drop your fuel mileage.FFT, Eric

 

Anything that helps airflow into and out of the engine, so intakes and exhaust systems

Anything that decreases rolling resistance: Air up your tires to max pressure and smaller tires help so don’t upgrade to big mudders.

Anything to reduce aerodynamic drag: a tonneau cover helps, biggest benefit is slowing down. Stay away from lifts.

Anything that reduces mechanical losses: Go to synthetic lubes throughout, lower numerical gears reduces engine friction.

Anything that increases the burn efficiency: Tuners increase the injection pressure that helps atomize the fuel better. and increase the injection advance to raise cylinder pressure for more efficiency. Fuel additive can help as well with cetane.

 

Wouldn't larger tires, to a point, help? Less revolutions per mile?

 

Taller not wider maybe. Taller would have more mass to spin up, bad in the city maybe ok on the highway. They would raise ride height though reducing aerodynamics.

 

the stock air filtration device is sufficent and the aftermarket does not provide a gain substantial enought to improve mpgs or power.
larger tires and even wheels increase weight. more weight less mpg
tuning plays a small role. on a 6.0 it is possible to gain mpgs thru tuning. the gains however are not as much as some people have claimed. i have seen 2-3mpgs more but usually see 1mpg solid over what i was getting stock. mpgs are simply a head game. if you were to start buying items such as a tuner, cold air intake, bed cover etc look at your total expense. you may figure out that the gains you got will take along time to recover in fuel savings. realisticly these trucks are 6k+ and that isnt light. how many miles per tank are the guys claiming 20mpg going?

 

quick update. i dont have any mods. well high idle and gutted kitty and straight pipe. Just had truck serviced. fuel filters and oil changed. Still same mileage. I did notice a weel ago my truck was missing or stalling out at idle after driving for a bit it has only done it twice now but something is up. Also my fuel guage seems to be off at times and never reads acurate to the amount of fuel in tank. I have tried different additives to fuel as well. something started acting up that has caused mpg to drop. its not gone out completely yet cause it still works but it concerns me a great deal. I have been noticing a stronger fuel smell at exhuast lately. when wot there is some smoke but it seems normal for a diesle to me>>>??

 

616 miles on 29.8 gals, its a pretty easy calculation.