Fuel filters and fuel mileage

[BB_TX]

My typical daily driving is 2 miles of narrow winding highway from my house with 45 mph speed limit, 1 mile of main highway at 60 mph, then it is city driving for however much running around I do. Then reverse back home. Mileage as shown on the computer has typically run about 15.5 both for my current truck and my previous 2007 F350 6.0.

Several months ago, that mileage for the same driving by the computer began dropping until it was down to about 13.5. That change, though concerning, was not accompanied with any noticeable change in performance, driveability, or towing.

Was considering taking it in for diagnosis. But two weeks ago, I took it for oil change and fuel filter change. After the fuel filter change, the computer is consistently showing 15.9-16.0 for the same driving. Over 2 mpg improvement. Have never had mileage drop like that before, on either truck. Or bounce up after a filter change. Anyone else ever experienced that?

[mlh]

I was thinks winter fuel but the mileage went back up. A lot of factors contribut to fuel mileage. Temperature, summer winter fuel, you to name 3. What you do not want is your high pressure fuel pump starved for fuel. That will wear it out and get in your pocket thousands.
Lynwood

[Larry]

I'm surprised that anybody trusts their computer to figure their mileage, what with VW paying billions in fines for lying about their mileage.

[BB_TX]

I calculate by pump and odometer when I want to know exact. But the times I have, that was within 1/2 mpg of the computer on this truck and my previous truck. The computer gives me constant feedback of any changes.

[richfaa]

My truck MPH indicator is within tenths of a mile of the calculated figure.... IF you fill the tank to its max capacity for the measurements.

Winter and summer driving does make a difference.

[mlh]

My F150 computer says 21.8 actual mileage is about 5% lower. That gives me about 20.7. Not bad for a 4700 pound truck that will turn a quarter mile in 14.7 seconds with a 164 cubic inch engine, or so says Car and Driver.
Lynwood

[1retired06]

quote:Originally posted by richfaa

My truck MPH indicator is within tenths of a mile of the calculated figure.... IF you fill the tank to its max capacity for the measurements.

Winter and summer driving does make a difference.

Agree, ours is pretty close as well.

[padredw]

I find that wind--even a very little bit of wind--makes more difference than any other factor. Over many thousands of miles I have used the actual mileage on the odometer and the amount of fuel added. Over several hundred miles and several refuelings the average has to be right.

[jcurtis934]

Noticed same pickup in mileage after filters changed. Also, when I had service on the dpf mileage went up dramatically... john