I didn't get mine for the great mileage either but, it is almost three years old now with 48000 on it and my mileage is getting worse. I have 2002 7.3L CC XLT 4X4 when it was new my avaerage was between 18.4 to 22.6 on a trip to South Nags Head I got 33.3 MPG, Now I know you can not expect that, we left at 2:30 in the morning and drove 60MPH the whole way. However, mine has gotten progressively worse since September, I went from roughly 22MPG on the high end to 17MPG then took in in for a reprogram and it went from 17MPG to 15MPG took it back again now I went from 15MPG to 12.4MPG to 13.8MPG on a good day. I calculate my mileage everytime I get fuel no matter how much and it is constantly going down. I really don't know what to do.

The only upgrades are a K&N Filter which I am **** on keeping it clean, tires upped from 265 to 285, and 4" exhaust was added. I use Pri-D everytime I fuel up. I have not done anything to the truck since September so I know it's nothing new in the mix.

I do have the premium extended warantee so I guess these guys are going to just have to keep seeing my every other week until it is fixed?

 

When i had 305's I couldnt get better than about 14.5-15,, Went to 285's and in the last 30,000 Miles I have averaged 16.9 and i idle ALOT. When i finished the first tank from the dealer i only got 16.2 with absolutely no mods, I to am **** about keeping records on everything i do with everything i own. None of the mods i have ever done made a bit of difference long as i drive it right,hammer it all the time and mileage drops big time. All I have for mods is SCMT on the 90hp program, straight exhaust, Kwik filter, HPX,2" leveling kit and Wastegate Unplugged.I tried several tiimes to get 20,, Drove like a grandma for 1500 miles on vacation last year and best i could get was about 18.5, And i'm talking No idle time, never over 65mph either. 90% of the time my Bass Boat is hooked to my truck,and i only drive 2 miles to the boat ramp,if its not my 36ft travel trailer is on its way to the deer lease or something. Pulling the travel trailer i do get 10ish, which dosent help my average any for sure.Overall i think it does very good,, Although i liked it better when Diesel was about 1.25 a gallon..!!

 

When I bought my truck milage was a factor but a very small one. I bought mine for the longevity and power. My '76 gasser was only getting 8-10 MPG (empty). Now I am getting 16-17 (hand calculated) with my PSD. I could never get good milage on the interstate doing 75-80 MPH, but in the last 6 months it has been holding at 17 MPG. This is with a mixture of driving but mostly interstates. I think it is finaly getting broke in (68000 miles).

 

I would bet money if MRB and F250 SD would go back to the tire size of the 265 you would see better fuel mileage. I see this all the time around here. Now don't get me wrong, I think the 285's look and are better than the 265's...Heck I put the 305's on mine as they just looked better for what I wanted from the truck. I was lucky in the fact with the 4.10 gears I have I gained fuel mileage.

Now I guess if money was not an issue, as it always is around my house, I would change the 3.73 gears you guys have and then you could put the bigger tires on and get better fuel mileage to boot. That would be what I would do if wanted to change things anyway. I personally don't think the mileage you guys have posted though is that bad for such a big truck.

You know with my past in circles I have been while working on outboards in engineering and special projects, I think the big auto manufactures are all in bed with the petroleom industry and they keep our fuel mileage right where they want it to be for the most part.

One reason I say this because some of us have done a few very simple things or seen some done that really increased mileage and performance. Now I am not over looking the epa ****'s either. I know they have to do things for the EPA and all, I am not taking about mods like that either. These guys are keeping our fuel mileage right where the petroleom guys want it. Really sick if you thank about that and see what the cost of fuel is now.

I worked in the petroleom fields and seen the diesel that is the very same way obtained from the fields was once cheap stuff, the cheapest fuel out there LOL Now we see this as the fuel of choice for many of us and now its the most expensive. I think our gov't. is bed with these guys as they have plenty of money to pad the gov't so that they would keep things honest LOL. Well I think we have seen that ain't going to happen LOL... So fuel mileage of my PSD as well as other vehicles I try to get the best I can with the fuel costs allowed to do what they have. JMO anyway.

 

alright, here is dumb question, if I change the gears to 4.10 ford say they will not warantee the truck anymore. I can't figure it out but it is what one of the engineers stated. My buddy has and 04 and is getting poor mileage on it and his ia all highway travel. We have been talking to the engineers to figure out what the heck is wrong with these things.

Any way what would be the average cost to change the gears to 4.10? I imagine it is going to be pricey since you have to do it on both axles.

 

Yeah the auto sucks for mileage. I had a shortbed supercab 6sp 7.3 and i got 20 mpg unloaded going 70. Now with my cc longbed 4x4 auto i get 16 mpg going 70. Sucks.

 

I have a Ford F250 diesel 7.3 and only got about 16 mpg until I installed a super chip (70 hp). I'm now getting 26 mpg around town and have been on highway yet.

 

Wow, I don't see how just merely changing the gear ratio to whatever you wanted or even thought you needed would void warranty. What am I missing here??? I would be all over this dealer to get to the bottom of that for sure. Maybe someone here will now more about this. I will be for calling my dealer to question them about something along this line in the morning, sure has me curious LOL...

Man I just went a looked at 05'MY new trucks this afternoon, found several that had tires that was 30.5" diameter with 3.73 gears too. They had 18" wheels with special ordered Toyo AT's on them too. I think everyone around here is about to get the handle on the new ones LOL... Yikes those King Ranch trucks are 50K too. I was shocked to see coil springs on the front axle on the 05's, didn't know they was doing that...Can't afford a new truck if I wanted one really, I plan on keeping the GWE longer anyway LOL...I like it just fine and have a few things I still want to do with her anyway.

 

Oscar, yo hand calculating those numbers?

I don't have the O/H console so the only way to get my numbers is the right way. You do have to fill the tank as much as possible to get real numbers.
I filled up this morning and removed the nozzle (just to see the difference) after the first "click" and have gotten 60 miles on the tank and the gauge is showing a little more than 3/4 full. Normally where the gauge is reading right now I should have 125 miles. If you want accurrate fuel milage you have to go to the pump, and fill it until it won't take anymore, than return to the exact same pump and fill it just like you did before. That's how I get my numbers. Oh yeah, I have the wastegate unplugged and 5.6K, that's it.

 

The onboard computer is calculating the mileage. In the past its been real close..especially in determing miles to empty and the amout of fuel it takes to fill it up.

 

haha, the chip throws the consoles way off.

 

Hey all,
I have a 97 f-350 with a 4.10. would bigger tiers help my MPG or hurt it. and would I need bigger wheeels too?, my tires are stock 285/r16 's I think ?? so should I consider different tires next time thankds J

 

WYC, I know my 95 PSD does better on the 305's. Not sure if you have any mods to the motor or not also, but I really like what the bigger tires have done and the mods to the motor.

 

Rowdy,

I dont have any thing to wild as far as mods just cheep, what i can afford kwiick filter, 10K gutted cat, thats it. so the 305 helped with MPG how about when towing do they hurt MPG bad?? J

 

Had a 2003 4X4 F250 SC with the 5.4 auto with 3.73's. I put 305's on it and it averaged 10-12 mpg. 265 miles to the low fuel light with no power. I now have a 2003 CC F250 4X4 7.3 auto 3.73's with the same 305's. I added a SCMT on the 90hp setting and a K&N. Lots of power. My last tank was 13.8 with the low fuel light on. 355 miles. My driving is 50/50 highway/city on hilly terrain. Neither speedo was corrected for tire size.