I have a 2017 F350 CCLB 4x4 Lariat Dually diesel. Completely stock. 15k miles.

When I first purchased this truck in January, I was a little dismayed at the fuel mileage - I was seeing around 13.5 - 14 cruising at 68mph.

At 15k miles, I am now seeing 17-18 at 68mph along the same stretch of highway. I'm not sure if this is due to engine break-in or a different "summer" fuel mixture, or a combination of both, but I am very pleased with the current numbers.

 

Mine has been dead on 17 from the first tank through my most recent tank at 25k miles. I kept looking for the "break-in" improvement everyone spoke of, but I didn't see it. I'm in South Carolina and I don't think there is a different summer/winter fuel here.
Billy

 

I have about 10K on my '17 6.7 now. I bought it last fall and most of the driving then was towing. Over the winter I rarely tow but daily drove the truck regularly, mostly in town. I have consistently seen about 15 over the winter but after filling the truck last week it has jumped to 17+. I assume that's due to summer blend?

My previous diesels I never daily drove so I had little data for comparison.

 

My mileage seems to be 14.5 and is awful compared to my 2005 Cummins I had before my F350. I sure hope it improves with break-in.

 

 

 

I've got 22,xxx kms on my '17 SD PSD, which I've owned for 7 months now. Lifetime consumption is sitting at 18.4 L/100, or 12.7 mpg. I do a solid mix of city and highway, no towing as of yet.

 

With 24,xxx miles on my 17 KR 250 (leveled w/ 295s) I'm lifetime averaging 13.5 mpg. Best I got was on my trip to the New Mexico mountains this weekend, 16.6; and before that was 16.2 on the same stretch. But it's no doubt due to the lower speed limits. It's hard to get anything over 14 when anywhere you go in Texas is posted @ 75mph!

 

You must have 3.55's.

I'm right at 15k now with my drw/4.10 and average 14 at best.

 

I don't believe in the mileage improving with break in. I'm on my 3rd 6.7 engine and I've never seen mpg improve as the trucks break in.
In fact my best mileage is the first tank. I think before the DPF starts to collect soot.

 

I feel like I got a good one. I am around 16mpg mixed driving. 3500 miles on it, hand calculated.

 

I have a 2017 F-250 Diesel Platinum Crew Cab 4x4 with 3.55. All stock. 20" stock tires. Just turned 9000 miles

Daily driver - 75 miles round trip - 70% highway- unloaded.

Usually get 17 mpg. If the DPF/DEF runs during a tank of fuel I'll see 14.5 during the regen, but still see about 16 mpg for the tank.

I usually add 4 oz of Ford PM-22 fuel additive at fill-up.

Jim

 

I'm at 13.9 lifetime with 30k miles. Leveled and 285's, and I really don't drive hard.

 

Yep, gears make all the difference in the world and winter mix does make a difference for those of us in the higher latitudes. I can tell in the last few weeks they have swapped to the summer blend in these parts. As to gearing, my F550 with 4.88 usually get 10 mpg unloaded........

I have 35" tires on my 2000MY with 3.73 gears, I can tell the difference from the smaller size I used to run as far as power and required points. I'm wondering about the new truck with 34" tires factory and 3.55 gears, I know there is more power but it seems like a very tall gearing to me, I guess I'll see but I'm expecting 18-20 mpg or so, least till I level it and add a huge bumper and winch.

 

2017 f350 crew 4x4 drw 3.55 gears 1900 miles. Pretty disappointed with the mileage, thought with 3.55 gears I'd get somewhere around 17 mpg. I'm only getting 12.5 mpg @ 70 mph. Drops to 10.5 mpg @ 80 mph. My 7.3 excursion with 35" tires on stock 3.73 gears gets 14 mpg @ 70 mph. My f250 on stock tires pushing 450 hp gets 22 mpg @ 70 mph. Im amazed with todays tech that fuel mileage is that of a gasser.