I had something strange happen this week that I can't figure out. I normally buy my fuel at TA, and I've noticed my fuel mileage going down the last three weeks, with no changes in driving or conditions. I could never get above 6.5 mpg with 45,000#, and then it went to 5.75 mpg.

I bought a load of fuel in Del Rio, Tx at a Town and Country, and my fuel mileage increased over 1 mpg, and the truck ran better, especially at higher speeds, and seemed to have more power.

I actually got 8.0 deadheading empty at 75mpg, where before the best I could get was 6.5. Under light load I was averaging 7.0 on hills with a headwind, and that had never happened before.

I'm really confused now as to what is going on?

Any ideas?

jonboy

There are a number of factors that can affect fuel mileage. Your decrease could have been something as simple as a strong crosswind or headwind. Fuel can also be blended differently, which might affect fuel mileage.

or perhaps you fueled while the tanks were being filled or right after, if you see a fuel truck offloading, dont get fuel, they stir up all the crap on the bottom, wait an hour or so, or go somewhere else.

There are only 1 or 2 fuel suppliers left in the US, most area truck/fuel stops buy from the same supplier, out of the same tanks

This is one of the reasons most gas/fuel trucks are no longer marked by brand name.

The company I lease to has a gas/fuel division and handles a certain east coast based convienience stores, the trucks are dispatched to the gas/fuel terminal by the lowest price, when you buy from these stores you do not know whose gas/fuel you are getting.

This is why when someone says they get better mileage when they fuel at the T/A for example they are really getting the same fuel that the Pilot or Petro has in their tanks, not much difference anymore.

I'd bet on winter fuel. They would have started using it in various places a month or so ago. The further south you are, the later they start using it. Del Rio probably never uses winter blend. I noticed my economy started declining 3 or 4 weeks ago. Does it every year about this time. The overall difference for me from regular blend to winter blend usually ends up being about .25-.3 mpg by the end of the season.

Bingo...give the man his cigar!!!

Another difference in fuel mileage now is Bio-diesel. Look at the pump when you fuel, and check for the BIO sticker. Pilot down here is selling 15% Bio, along most of I-10 from Houston to Mobile. The J has been selling regular #2 diesel, as well as 20% Bio, over most of the south, since about mid-july. I haven't seen Bio at TA or Petro yet, and haven't been buying at Loves.
Learned(3 weeks ago) from one of the driver's of an Austin area Bio-manufacturer, that they were having thickening problems with the fuel last year, when they switched all their road trucks and diesel pickups over to 85% bio. They ended up installing fuel tank heaters on the road trucks, to over come the problem. The driver didn't say what they did about the pickups. Who woulda thunk that peanut oil would get to thick to move!!

in the winter months fuel m.p.g. can/ will drop slightly. though having the wind at your back instead of coming at you will make a huge difference. thats why areo trucks can get better fuel mileage. i find usually when my fuel mileage drops noticeably, it's something like a pin hole in the air to air line or air filt needs changing, overhead needs to be run, e.t.c. the load can also make a diff.. i have a flat top & one time while hauling pallets 13 ft high. i drove 280 mi from lou ky to htsvl al and my truck could not get over 65 m.p.h. & had a hard time getting past 55 because of the wind resistance & the head wind i was fighting. i got 4 m.p.g. when i used to get 6.5 m.p.g.