Going up I filled in Lubbock, then again in Taos NM, have no idea where winter grade is at the pumps????

I live outside San Antonio, its 1105 my time and the doors are open in the house, will be in the low 70's today. In fact on 30 Dec I was out working on the place and had my shirt off, sweating like lived in Alabama and had not paid my poll tax and George Wallace was the governor...IIRC it was almost 80.

 

Winter diesel.
I see this every single year.

 

I assume your fill up at home was not winter diesel since you live in the Banana belt. But it probably was winter diesel as you got closer to colder climates

 

I normally purchase my fuel at BP stations due to the rewards program. I normally get between 400 and 460 mpg loaded and 460 to 520 empty. A few days ago I was in Colorado and bought a tankful of Sinclair fuel. I got 950 miles out of that tank! I was amazed and thrilled, so of course I hit Illinois which had no Sinclair stations, so I bought a tank of Shell. The mileage wasn't nearly as good, but still better than the BP fuel I normally use. Then, when I hit Indiana I bought a tank of BP, which didn't even give me 400 miles (empty)!
However, I also noticed a sticker on one of the pumps at the Shell station - it said something to the effect that this fuel is not a Shell product.
So I've learned that diesel fuel is not necessarily produced by the company whose sign is on the pump, and the (I'll call it quality) of the fuel can vary widely.
It seems to me that if we can't count on consistent performance from the fuel we use, it's pretty much impossible to predict in any meaningful way the performance of the truck we use that fuel in.

 

Because of the recent cold snap, a lot of fuel companies were caught off guard by how chilly it got and the fuel did not have enough #1 diesel in it. Lots of gelled up trucks, and lots of complaints. The gas station where I bought diesel from is reimbursing me for the cost of filters and a couple of tanks of diesel. I bet they are having to make a lot of similar claims. Point is, now they have between 80-90% #1 diesel in the tanks, and fuel economy is simply atrocious. You are mostly burning kerosene, and you get a lot less power out of it which results in terrible economy. My fuel economy is drastically down. Because of this, its possible even in your sunny and warm area, you encountered some winter blend diesel. That's my hypothesis.

 

Are you on 75 most of the way?

 

 

What makes that strange is that there are no hills from Toledo to Cincy. Weird

 

It's been -30 or lower here for the last week or so.
With the increased idle for warmup, and the blend of fuel (not to mention moving thick oil and frozen parts) there will be no high mileage economy.

 

I did the same route in the other way last October and my MPG was 11.85 and 10.44 with a load of 14500 lb.

 

One of the things I have noticed with my 17 vs my 11/15 is that mpg is really all over the map. Drove into San Antonio Fri, wow, everybody must have been off work as it heavy traffic. I got 21.2 going down and it dropped to 17.9 coming back, but had a lot of sitting still on Interstate heading home, now that about 70 mi rd trip for me.

Oddly the 21.2 is my best, just wondering if a bit less traffic I could have seen more I am sure... This is running about 68-72 mph, you have little choice in the matter, slower than that and you make a lot of people unhappy in spite of the danger of the 'canyons' where we just had a 4 18 wheeler pile up and I have no idea how many passenger cars were involved. 2 of them were hauling brand new cars, on laying on its side, the other jackknifed., the other 2 were box trailers, one on its side the other jackknifed. It was a mess to say the least. BUT they are working on I 10 in in the canyons there is NO, ZERO shoulder at all, the white line is a concrete wall on both sides, making the road about 16 ft wide for 2 lanes...white knuckle driving.

 

I always get around 8-9 mpg when towing our Travel Trailer. If conditions are perfect, I may get up to 11mpg for short periods. But, 8-9 is about right. 2016 F-250 gas. Just got a new 2018 f-250 with the 4.30 differential, so we'll see if that makes a difference.

 

I myself have also noticed a drastic change in my fuel millage in the last two fill ups. I drive my truck mostly to work and back empty as a daily commute. I drive 15 miles back country roads average 55mph and 20 miles high way 75mph. I purchased the truck new in July I have gotten a consistent 18-19 even the occasional 20 mpg. With the last two fill ups I am down to 13-14 mpg. Same exact driving conditions, idle times, morning warm up times in the driveway. It has also been below freezing here for a few months so I don't believe the temperature is playing a major factor. The only thing that has changed on the truck is that I had the dealer do my first oil change at 8500 miles. I think it is just a major coincident but after that oil change is when my mileage went south. I have never heard of any time that an oil change would effect mpg's but it is strange. Could the truck be stuck in a regen?

 

Well, I've had a lot of f250's and I've never gotten 18-20 mpg on any of them. The best one was a Diesel that I got maybe 16-18, but it went down dramatically when I towed...to around 8-9mpg. Diesels tend to have a bigger drop off when towing, not sure why. All my gas 250's usually get around 14-16 regular driving and on highway and 12-14 in city. 8-9mpg towing. It's always been that way for me and most people I've talked to. If I'd got 18-20 at any time I would have been ecstatic, lol. So, I can't tell you why you were getting such good mileage early. I would talk to someone from Ford itself, some type of engineer and see if they have any idea. If there's a secret to that, or something they did initially (different gas, a temporary computer setting, weird experimental oil, lol)...I think a lot of us would like to know. Maybe something was off on the Trucks MPG computer calculator. Did you change your axle differential? I don't know. You've certainly had enough trucks to get a feel for what your gas mileage should be. But, I've never gotten anything like what you have. Maybe your outside-of-the-city driving helps. But, what you're getting now, is what I've always typically got...unfortunately. Btw, I'm in San Antonio too. Schertz, actually. Howdee neighbor

 

Fuel quality indifference possibly? I seem to notice some difference between fuel at some/ (rare) fill-ups. I will usually option over to the instant MPG meter, then start to figure out the basics like wind, elevation climbs and then regens. Then after this checklist I start thinking about my last fill up.

I know for a fact at a BP station that featured "Premium" diesel and "Regular diesel" at the pumps, I chose Regular and it was horrible, and a very noticeable drop in mileage. My thinking was (after) that the so called Premium was probably really normal diesel, and the Regular was some low cetane or recycled chicken wing oil.

So fuel grade could be a thought.