Well let me first say that I absolutely love my new truck. It is a CCSB 6.7 KR. Love the interior, the ride, the power, the looks. Actually I pretty much love everything about this truck even the stereo which gets so many complaints on here, and then there's the fuel mileage👎👎👎.

At first it seemed it would be pretty good because on my first tank which was 80% around town it averaged 14.5 which was a little better than both of my previous cummins'. Then came the first trip I was hoping for 18 but pretty much expecting 17 at 70mph. Well how about 13.2😡😡😡. I couldn't believe it and since then have tested multiple other highway 70-75 mph trips with the best one being 14.9.

I talked with the the service advisor today who said bring it in they would re flash it but other than that not much they could do. My reply was that if it doesn't improve I would need to speak with a ford area rep because I didn't spend 8500 for the diesel to get the same fuel economy as the gasser.

Any suggestions and is anyone else seeing this bad of highway mileage or am I correct in thinking that this is unacceptable???

 

What truck do you have? Gears? Tires?

 

It is a ccsb f350 3.55 same situation with both stock tires and 285 75 18 mt's that are on it now.

 

I had a 2012 6.7 KR CC SRW LB on stock 20s. I was getting pretty much the same thing. I deleted mine and jumped to 20 on the highway and 15/16 in the city.

 

You can't run MT's and then complain about mileage, regardless of the size. The increase in rolling resistance is significant.

 

Well, a 35 inch mud tire is going to chew into your fuel economy no matter how you drive.
At 75mph even a bit of wind or rolling hills will use fuel.
And you are going farther and faster than you realize with the 2 inch+ larger tires.

 

I hear ya but not looking to delete it yet with only 2000 miles. Mostly because there really isn't any good deleted tunes out yet for the 2017's

 

The tire is 3/4 in taller than my factory tires I understand the mt has more friction on and on the point is it was terrible with both the factory tires and actually seems a tiny bit better with the 35 mts but both seem to be unacceptable for a diesel

 

my lifetime is at 13.9


don't care but i was a big block guy from back when you could still buy one so that suits me just fine

 

The big question is... is anyone else seeing 13-14 mph on the highway with a single rear wheel?

 

My lifetime on the dash says 11.9

 

I'm looking at deleting my 2017 F450. Ive been looking at Nally Diesel Performance. You have enough miles to delete now. If I remember right I deleted my 12 at 800 miles. I always left the programmer in stock mode. Truck ran great.

 

Not as much worried about the lifetime as I have towed, used the remote start... but when reset on a trip and hand calculated on highway that is when I have a problem with it.

 

Your mileage will increase as it breaks in. I have 11K miles now and get about 17-18 on Colorado hi way speeds at 7000' elev. stock with same setup.

 

My mileage shows 19.4 mpg current, and 17.7 lifetime. I have stock Goodyear 275/70r18 all-terrains, 2.5" leveling kit, and 3.31s