Combined milage on trip So.Cal. to Washington 3,500 miles ,low was 11 mpg, high was 14.4 mpg. 05 F250 CC/LB 4x4 4.10

 

well
1st tank 10.8
2nd 8.44
3rd 8.40
4th 8.0

It keeps getting worse--what gives?

I drive with a very light foot--I havent even revved the motor over 3000rpms
yet

 

Do you hand calculate the milage or use the overhead computer ("lie-o-meter")?

If you use the overhead, make sure that you reset it at each fill up by pressing the two buttons at the same time.

Still, reset or no, that sounds pretty awful

 

Mine's an 04 but it did the same thing. It did really well on the trip back from NY, averaging about 13mpg with mostly interstate driving. When I got back the first tank was 10.5mpg and proceeded to fall...all the way down to a worst of 7.02mpg with combined towing and non-towing around town. It stayed in the gutter for about a month, ranging from about 7.4 to about 8.2mpg. Whether it was towing or not, around town mileage sucked. Then I started experimenting with different brands of fuel. I had been using Sunoco and Chevron. I finally put a tank of Hess in and it spiked to 9.8mpg, same kind of driving. It does pretty good with Amoco too.

I thought I was probably reading a little too much into it, so I put Chevron back in it the last tank. I don't know how to explain it, but immediately the truck felt like it had less power, almost like the parking brake was a couple clicks down. I tried to pay no attention to it, but on the next fill mileage was down over 1mpg again, back into the 8's I don't know what they are pawning off at these Chevron stations, but my truck does not like it. It likes Sunoco even less. No tank of Sunoco ever did better than 8.02mpg. Chevron has never reached 9mpg. Hess has consistently gotten 9.25 to 10.5mpg. I haven't used enough Amoco to come to any conclusion, but the three tanks have been in the same range as Hess. Best tank ever...FlyingJ That was on the trip back from NY, 13.77mpg. That was quite a bit of interstate driving, but a fair share of in-town and driving through the Blue Ridge Parkway.

One more thing, I babied it for the first month. Driving it a little more aggresively, not beating the crap out of it, the mileage actually went up

 

these are hand calculations--i do not have the built in meter

I think Im gonna cut down my morning warm up time to a minute or 2
I bet this thing just makes a gulp gulp gulp sound at idle

I was driving a chevy with the 8.1 and allison trans b4 and that got
5\6 mpg loaded\unloaded now thats horrible
I hope Im not heading down that low with the 10

any tips----? sound like a have a problem with truck?