I drove from MIAMI to ORLANDO & stayed a week driving around the city & average 16.7 MPG

 

I know your question is a couple of years ago, but I have an 08 6.4 and I been seeing 14city and 22 on the highway. This is total stock and on the flat lands of South Florida, 100k miles.

Just keeping on topic ( to those of you non 6.4 owners that posted)

 

14-15 city before fuel filter change
16.5-16.9 city after fuel filter change (hand calc always)

19-20 hwy before filter change
21-22 hwy after

2008 6.4 CC SB 4x4
DPF/CAT/EGR Deleted
5" turbo back exhaust
running Spartan 275 el tune (she's a beast)

 

Hey guys just totaled my 6.0. i'm looking at getting a 6.4. i have been really looking at mpgs this time around. My 6.0 was horrible. I noticed everyone was mentioning their upgrades, but nobody was talking about the gear ratio. If a truck has 3.55 gears instead of 4.10 gears wouldn't that be a game changer when it comes to mpgs? Thanks guys.

 

My condolences on your loss. I was finding 05 to 07 6.0 trucks from $9K to $18K depending on miles. noticed the 6.0 was way louder and with the cascading failures in the engine I opted for the 6.4L, fairly proven engine. I think it depends on what your planning on towing if it's not much stick to the 3.55 gears. read up how to tell by reading the diff before hitting the used lots.

Your worried abut MPG , I think gears would play a little difference , more importantly would be those low rolling resistance tires and most of all driving habits. I found I get the best highway MPG on the highway staying around 60 mph and a trip from miami to orlando was about 23.7mpg. Mind you I had everyone and their grandmother throwing the finger at me on the highway on the way. That 23.7 was from exit ramp to exit ramp after filling the tank and verifying it with another filling at another station divided by miles ( to pretty much verify what the computer said).

Take care of your fuel filters, substitute 1 gallon of your oil for that lucas additive between oil changes.

Keep in mind it's a 8,000lb truck.. what the frick do you expect?? if MPG is a big deal buy a matrix then tint the windows to hide your shame.

 

I understand its a 8000 lb truck. And Im not expecting 25 mpg or even 20. I just want the old 7.3 reliability and mpgs. I know the whole emissions deal and new techology, but that doesnt make it right to justify 10 or 12 mpg unless people are buying them equipped that way and not saying it when they complain.

 

I'm only getting 14.6 MPG in the city from my 2008 F-250 6.4 2WD

 

I changed my rear tires from 265/70/17 to 235/80/17 & I went from 14.6 mpg to 15.28 mpg in the city

 

I just picked mine up from texas 3 weeks ago. Its a 2009 f350 crew cab long bed lariat with 3.55 gears. It got 15.3 all the home no matter if it was 80 thru texas or 70 thru alabama. Now that i am home in west virginia its getting 13.3 all day long. I cant complain through thats on stock tires and no mods done (not even a cold air kit). And thats way better then my studded cold air 5 inch exhaust tuned 6.0 EVER got. LOL... After looking for over a month and driving 10 different trucks before I bought the gears in the rears of these trucks determine more about the mileage the people are willing to admit. But thats just my opinion. I got what i wanted. Thanks for all the info guys...

 

Changed the alternator on my 08 2 weekends ago. Of course disconnected the batteries. After the reset. I drove like grandma for a week and was getting 17.2 on the dash. (I know they lie though) Just to see what it could do before I deleted the DPF. 45-55 mph non highway.