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'08 F-350 SD 6.4L Mileage questions


Herdfan

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I recently purchased a used, yes used, '08 F-350 SD, CC, 6.4L Auto, 3.73. The original owner had it for 2 months and put 1800 miles on it. So I called him and asked him why he got rid of it and he said he was a Chevy guy and tried the Ford, but had to go back to a Chevy. This made sense as I bought it from a local Chevy dealer.

 

Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

 

The truck runs great. It does not seem to be stuck in regeneration and the power is smooth with no hickups, so I am guessing I don't have the injector issues, (Truck hit the selling dealer in 4/07, but not sold until 9/07).

 

So I was wondering a couple of things. Should I be getting better mileage and what RPM's are you all seeing at say 70 MPH on a flat road? At first I thought it might have the 4.10 gear, but I got the selling dealer to order me a window sticker and it has the 3.73.

 

Thanks for the input.

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I get about 15 mpg on the highway at not over 65. If I take it up to 80, I can almost see the fuel gauge drop. Sounds like yours is a Job 1, and I think they have a reflash available that might help a little. I also have a 3.73, and see 2,000 rpms at 65 mph. 17" A/S tires.

Edited by ab257
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Your truck sounds on par with most. Driving 50/50 and not taking off like a snail i can get high 12's. If I baby it by never going over 70mph, creep from a stand still, and coast a long distance to stops I can muster high 13's. If it's just all highway and not going over 70mph I've seen 17-18mpg. But, as soon as you go over 70 it's murder on fuel mileage. The key is keeping the boost below 20psi from dead stops and below 10psi while driving. At 70mph I'm right around 2,000rpm's. I've got the F-250 with 3:73's and 18" wheels, she's a heavy pig clocking in at 8,400lbs with a full tank of fuel and me in it (150lbs).

 

I also forgot to add that towing SUCKS, fuel that is. It tows like a beast but also has an appetite to match. I recently yanked our little 7K lb toyhauler and never got better than 9mpg. I will be going back to the F-150 once they release the 6.2L. The main reason is fuel prices. Diesel cost 50-60cents more per gallon than regular 87. I was also getting that mpg from my 2003 F-150 (5.4L) while towing and always got 14mpg mixed driving. It did not tow as easy but the cost of fuel is rediculous along with diesel maintenence. I want a simple gasser that only needs $30 oil changes and a fuel filter every blue moon.

Edited by Hydro
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Sounds like yours is a Job 1, and I think they have a reflash available that might help a little.

 

Thanks for the replys. I took it to my local dealer for an oil change and asked them if an update was available. He said it already had it and the selling dealer must have done it before delivery.

 

I have a heavy foot and I drive 75+ on the interstate, so I am going to guess that is the source of my mileage woes.

 

Thanks again for the replys.

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I recently purchased a used, yes used, '08 F-350 SD, CC, 6.4L Auto, 3.73. The original owner had it for 2 months and put 1800 miles on it. So I called him and asked him why he got rid of it and he said he was a Chevy guy and tried the Ford, but had to go back to a Chevy. This made sense as I bought it from a local Chevy dealer.

 

Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

 

The truck runs great. It does not seem to be stuck in regeneration and the power is smooth with no hickups, so I am guessing I don't have the injector issues, (Truck hit the selling dealer in 4/07, but not sold until 9/07).

 

So I was wondering a couple of things. Should I be getting better mileage and what RPM's are you all seeing at say 70 MPH on a flat road? At first I thought it might have the 4.10 gear, but I got the selling dealer to order me a window sticker and it has the 3.73.

 

Thanks for the input.

 

 

I also purchased a new F-350 crew cab 4X4 with the new 6.4 diesel. and boy what a great truck. nice to drive and it rode nice beautiful interior and dash but when it came to fuel economy it roialy suck big time 10 to 12 under normal driving conditions but towing our 30 foot 4 horse trailer it would not pass up a fuel stop. our trailer weighed around 12 to 13 thousand loaded and the very best we got on the interstate was 6.5 or less and now that hurt big time but i got it all fixed now and am getting 14 to 15 with the 12 to 13K load and 18 empty. ( i purchased a new 2008 dodge)

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I recently purchased a used, yes used, '08 F-350 SD, CC, 6.4L Auto, 3.73. The original owner had it for 2 months and put 1800 miles on it. So I called him and asked him why he got rid of it and he said he was a Chevy guy and tried the Ford, but had to go back to a Chevy. This made sense as I bought it from a local Chevy dealer.

 

Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

 

The truck runs great. It does not seem to be stuck in regeneration and the power is smooth with no hickups, so I am guessing I don't have the injector issues, (Truck hit the selling dealer in 4/07, but not sold until 9/07).

 

So I was wondering a couple of things. Should I be getting better mileage and what RPM's are you all seeing at say 70 MPH on a flat road? At first I thought it might have the 4.10 gear, but I got the selling dealer to order me a window sticker and it has the 3.73.

 

Thanks for the input.

 

 

I also purchased a new F-350 crew cab 4X4 with the new 6.4 diesel. and boy what a great truck. nice to drive and it rode nice beautiful interior and dash but when it came to fuel economy it royaly suck big time 10 to 12 under normal driving conditions but towing our 30 foot 4 horse trailer it would not pass up a fuel stop. our trailer weighed around 12 to 13 thousand loaded and the very best we got on the interstate was 6.5 or less and now that hurt big time but i got it all fixed now and am getting 14 to 15 with the 12 to 13K load and 18 empty. ( i purchased a new 2008 dodge)

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Thanks for the replys. I took it to my local dealer for an oil change and asked them if an update was available. He said it already had it and the selling dealer must have done it before delivery.

 

I have a heavy foot and I drive 75+ on the interstate, so I am going to guess that is the source of my mileage woes.

 

Thanks again for the replys.

 

You might try the Job 2+ front spoiler, as long as you're ok with the looks -- it will be mostly effective at hiway speeds, and most that have switched to it are reporting 1 - 2 mpg gains...

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  • 3 months later...
I also purchased a new F-350 crew cab 4X4 with the new 6.4 diesel. and boy what a great truck. nice to drive and it rode nice beautiful interior and dash but when it came to fuel economy it royaly suck big time 10 to 12 under normal driving conditions but towing our 30 foot 4 horse trailer it would not pass up a fuel stop. our trailer weighed around 12 to 13 thousand loaded and the very best we got on the interstate was 6.5 or less and now that hurt big time but i got it all fixed now and am getting 14 to 15 with the 12 to 13K load and 18 empty. ( i purchased a new 2008 dodge)

the mileage issues are a result of ford meeting the 2009 emission restrictions a year early. every brand will face these same issues.diesel mileage is gonna suck til the technology catches up or the restrictions are changed. what good are low emisssions if you use twice the fuel???

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the mileage issues are a result of ford meeting the 2009 emission restrictions a year early. every brand will face these same issues.diesel mileage is gonna suck til the technology catches up or the restrictions are changed. what good are low emisssions if you use twice the fuel???

 

 

I dunno, clean air is kinda nice.

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I dunno, clean air is kinda nice.

 

point taken,consider this:

 

even though the emission standards are higher,in order to balance out the almost 50% mileage decrease emissions would have to be decreased by half,right. did this happen? ummmm no it didnt. the net result,an increase in fuel consumed AND emissions.also,due to the lack of efficiency of these vehicles, older,more polluting diesels will stay in service longer. the net result? more emissions. so yeah clean air would be nice.

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point taken,consider this:

 

even though the emission standards are higher,in order to balance out the almost 50% mileage decrease emissions would have to be decreased by half,right. did this happen? ummmm no it didnt. the net result,an increase in fuel consumed AND emissions.also,due to the lack of efficiency of these vehicles, older,more polluting diesels will stay in service longer. the net result? more emissions. so yeah clean air would be nice.

 

 

I'm talking about the emissions that are harmful to us like NOX. They have gone down significantly and needed to.

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  • 3 months later...
I recently purchased a used, yes used, '08 F-350 SD, CC, 6.4L Auto, 3.73. The original owner had it for 2 months and put 1800 miles on it. So I called him and asked him why he got rid of it and he said he was a Chevy guy and tried the Ford, but had to go back to a Chevy. This made sense as I bought it from a local Chevy dealer.

 

Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

 

The truck runs great. It does not seem to be stuck in regeneration and the power is smooth with no hickups, so I am guessing I don't have the injector issues, (Truck hit the selling dealer in 4/07, but not sold until 9/07).

 

So I was wondering a couple of things. Should I be getting better mileage and what RPM's are you all seeing at say 70 MPH on a flat road? At first I thought it might have the 4.10 gear, but I got the selling dealer to order me a window sticker and it has the 3.73.

 

Thanks for the input.

 

Keep in mind your truck will give better gas mileage as you break in the motor.

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Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

The speed is your problem! I have a 2001, with same configuration as yours. I get the same mileage (12.5) pulling my 9500lb. travel trailer at 55mph as I do unloaded at 75mph. Every since diesel went through the roof I tried slowing down to 60 and taking off a little easier. To my surprise I now get around 17 mix HWY/city, and I have gotten as high as 21 on a long interstate trip. It's REAL hard to stay under 60 with the road tractors and idiots flying by you at 80+, but maybe worth it until fuel comes down.

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  • 2 weeks later...
Keep in mind your truck will give better gas mileage as you break in the motor.

Not true with the 6.4L.

On every truck board I visit people range from 20-80K miles and nobody has seen improvement. The only true way so far is to ditch the f*cking DPF. People running the Spartan tune with DPF delete are getting the most gains. It is not uncommon to see 21-23 MPG out of the 6.4L with the delete kit. Oh yeah, the extra 210-250 hp is icing on the cake!!!!!

Check out everybodys praises at http://www.thedieselgarage.com/forums/forumdisplay.php?f=162

spartandieseltech

Edited by Hydro
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Not true with the 6.4L.

On every truck board I visit people range from 20-80K miles and nobody has seen improvement. The only true way so far is to ditch the f*cking DPF. People running the Spartan tune with DPF delete are getting the most gains. It is not uncommon to see 21-23 MPG out of the 6.4L with the delete kit. Oh yeah, the extra 210-250 hp is icing on the cake!!!!!

Check out everybodys praises at http://www.thedieselgarage.com/forums/forumdisplay.php?f=162

spartandieseltech

Mhm my freind went from a 7.3 to a 6.4 and was very dissapointed in the fuel economy until he deleted the DPF and went with an Edge ( I think) tuner and the truck gets up to 22 on the highway now and absolutely screws ( Also blows a ridiculous amount of black smoke now too). Just rip that DPF off and go drop it off on the EPA's front door!

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You might try the Job 2+ front spoiler, as long as you're ok with the looks -- it will be mostly effective at hiway speeds, and most that have switched to it are reporting 1 - 2 mpg gains...

 

What spoiler are you talking about? Can you post a picture . I am not sure I have it. My truck was built in December 2007. I tow also and could use the extra milage around town.

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What spoiler are you talking about? Can you post a picture . I am not sure I have it. My truck was built in December 2007. I tow also and could use the extra milage around town.

Look at the front of the truck under the bumper. You will see a black plastic spoiler there. Job 1 had a small spoiler, while Job 2 and later has a spoiler that is about 5 or 6 inches.

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  • 1 month later...

That's all your going to get. I have a 08 and with 4:88 and the best I get at 70 is 10.5 and at 60 11.3, sorry to say.

I recently purchased a used, yes used, '08 F-350 SD, CC, 6.4L Auto, 3.73. The original owner had it for 2 months and put 1800 miles on it. So I called him and asked him why he got rid of it and he said he was a Chevy guy and tried the Ford, but had to go back to a Chevy. This made sense as I bought it from a local Chevy dealer.

 

Anyway, I have been getting somewhere around 11-12 mpg doing mostly interstate driving. I recently took it on a 500 mile trip and even then could not pull 13. Now I drive somewhere between 75-80 on the interstate with the CC set.

 

The truck runs great. It does not seem to be stuck in regeneration and the power is smooth with no hickups, so I am guessing I don't have the injector issues, (Truck hit the selling dealer in 4/07, but not sold until 9/07).

 

So I was wondering a couple of things. Should I be getting better mileage and what RPM's are you all seeing at say 70 MPH on a flat road? At first I thought it might have the 4.10 gear, but I got the selling dealer to order me a window sticker and it has the 3.73.

 

Thanks for the input.

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Dealer here has an '08 F350 dualie, regular cab 4x4, 6.4, 3.73..what kind of mileage would it get?

 

I am quite taken with this truck. I don't haul SQUAT, but this truck is just BADASS. It's red, looks like a goddamn diesel hot rod. I'll cry if it only gets like 14 mpg.

Edited by Hellcat
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