I have read that people with Diesel F-250 and F-350 get 17 to 20 MPG. I just calculated my mileage and it was 15.17 mpg. What am I doing wrong? I drove to Va. and then drove home. This week I went to work and rode around then tonight I filled it up anddid my math. I drive @ 55 mph. Kept my RPM under 2000. My mpg stinks and what can I do to improve it and get mileage like everyone else?

 

Sam that is about all I am getting with my 03. I may get up to 15 mpg's but nothing more. I am stock too. No big tires or lift or anything.

 

Your 03 gets 15 mpg! I read people doing much better and my mileage stays at 15. My truck has a catalytic converter on it plus wide tires. My 2000 F350 7.3 did much better than my 2005 F350.

 

I also still have a catalytic converter. I have gotten as high a 17mpg on a trip, but that was a flat land trip. No big mountains.

 

I guess that is the best I can get. I do not know how people get 18 out of there trucks.

 

If I may ask do you use cruise control on long trips? thats how I get 34 with the fusion

 

But if my mother drives its 15mpg, don't know how she does it and ford doesn't know either.

 

I think people to tend to inflate there numbers a bit 14 to 17 on average for a tank sounds about right to me. 17 to 20 sounds a bit inflated, a lot of cars are only getting 20

 

My buddy has a I think a 02' F 350 Diesel, he swears it gets over 20 mpg. He has some sort of chip in it and a K&N filter in it. I'll see if I can find out more. I'm getting close to 21 with my new truck which is a 4.6. Rear gears imo have as much to do with mileagae as anything. My 05' had 4.10's, could rip a stump out of the ground but 14 mpg was the max. my new truck has 3.55's.
Charlie

 

You may have nailed that Charlie, I didnt even think of the gears my truck with a 5.4 (and big tires) gets around 14 average and it has 373's

 

Sam I got almost 21 mpg the way home from Carlisle doing 75 mph, very little stop and go. It seems I can get better mileage at higher speeds than doing 55. Around town I ave 14 to 15 mpg. When I'm towing the landscape trailer with a load, around 8--10 mpg.

How much does the truck sit and idle? That will kill your ave.

From all in the 6.0 forum, Ford has the best air filter for the 6.0. I don't know since I still have the stock air filter.

When was the last time a Ford dealer flashed your computer? It its never been done, then have it done. There were some updates that helped with fuel economy.

I had a reflash right before Carlisle ATN's and it made a big difference.

 

I keep my motor,trans and rears stock. I change all mt filters and fluids. My truck has 33" tires and 13.50 wide I know this hurts my mileage. I have 3.73 gears. And I use my cruse control. I can not travel through Delaware and Maryland at 70 MPH and not get pulled over.
My dealer is not the best. They flashed my truck after I got it in 2005 and I lost 2 MPH. I told them and they said that was impossible! It lost the mpg and on a long trip I noticed it right away. They also sold me the tires I have now.The dealer said they were the best option for my truck in tire size so I purchased them and 6 months later they told me it would not pass inspection. The tires stuck out past the wheel wells. I lost all faith in Ford Dealership.
That is why I trust the information I get from everyone with the Delaware Chapter.Everyone has been a big help with my mods or questions like my mpg's

 

Sam on your way down south, make an appointment at Frederick Ford, just south of Seaford. They have always treated me right, and are on top of the latest flashes.

Did your speedometer need to be recalibrated with the tire change?

There's not much road, except for Rte 1 where you could do 70 and not get stopped

 

I had my plugs changed there in my old 1998 F250 5.4 while I waited. I did that one time and never again. I thought about it but after what I got around my area I was afraid to let them touch it. I don't mind to pay for it just do it right.I am going to call them Saturday and find out about it Thanks.

 

I was getting 18-19 on trips to NY and back when I had stock tires on my truck and 15-17 from home to work and back. I never got the speedometer recalibrated with the larger tires and I got 16 on my last trip to NY. I have been getting 14.5-15 or so from home to work and back.

But my truck isn't stock anymore either.

Mark