Can someone explain this to me....

[Jspafford]

Towing with my F-250. This past week I was using my truck to tow some RV's for my employer. I have been keeping tabs on my gas mileage for the last 9 months. I have a spread sheet with, date, gallons, miles to fillup, price, etc and it tells me my average MPG per tank.

So I towed two trailers. One was a 26' which was about 6,000lbs. It was 33 miles one way, and on the way back I was not towing. It was mainly interstate, but there were some stop and go spots too.

The second trailer was 32' and I would guess about 8-9000lbs. It was the same 33 miles.

Anyway, When I filled up and averaged my mileage I got 13.94 mpg. I normally get between 11.5-13 without towing. I almost got 14mpg with a WHOLE lot more weight. How is that even possible? I was practically flooring it up entrance ramps and only hitting 35 at the tops. All in all the truck was bustin it's ass getting these things moving and it gets better MPG's than when not towing at all.

Im stumped

2002 F-250
5.4L Triton 2V
4R100 Automatic with 3.73 gears.

Could it be that when in OD the motor is lugging and that by keeping it revved like I had to a lot of the time, it was burning cleaner??

 

[Wicked_Sludge]

does that 11-13 figure include daily commuting, errand running, and grocery getting type driving? making lots of starts and stops during a tank can dramatically lower your mileage. its possible that since you were on the highway for most of this tank, all you saw was highway mileage (even though you were towing).

that combined with the tranny staying out of OD (keeping the engine in its powerband) may have added up to higher mileage.

 

[AllanD]

If you were towing with OD "Locked out" then it indicates that you
probably have gears in your F-250 that are simply too tall.

I've recommended that to people when they were debating a gear swap.
Try driving the truck for a week without using overdrive.

IF you get better mileage do the gear swap without delay

AD

 

[Jspafford]

Allan, to be honest I left it in OD, and it only popped out once or twice when trying to accelerate on the highway.

It did however rev a lot higher and longer than it usually does in each gear getting the load moving.

The truck has 3.73 gears. I wish it had 4.10's.

 

[Will]

I'm yet to see a truck get better mileage when towing. It defys reason so I would suggest a problem in the test.

The shortness of the trip probably has a lot to do with it. You're only burning off 3 gallons so a difference in when the pump pops off would be small and make a huge difference in calculation. Pull one of those trailers for a whole tank and you'll get what you expect.