Well I keep track of my fuel mileage after every fill up. I generally average about 14 on a mix of highway and city driving. Never have I been over the rated 16 highway MPG.
Tonight somehow I apparently got 18 MPG. I noticed my gas gauge was at 1/2 tank but the fuel pump clicked off at 9.492 gallons which doesn't add up (27 gal tank). So I checked the fuel gauge afterward and it showed I had a full tank. I know my mileage is correct because I check both the odometer and trip meter and it showed I went 171 miles. So WTF? I'm pretty sure 18 MPG is impossible in my truck especially on my average city/highway driving. Maybe the pump was wrong and gave me more fuel, I don't know. That would be cool.

Is anybody on Fuelly? Here's mine.
http://www.fuelly.com/driver/jp2085/f150

 

That's pretty sweet.

 

I have done 15,7 MPG on my last tank...pretty much half of it highway. at 65-70mph
that's the best I have ever done in a mix cityhighway.

My best ever, only highway, is 17 but at 70mph. pretty sure it's easy to do 18mpg at 60mph

18 mix city/highway..you got a featherweight foot

 

I get on average 18 driving highway to work and 16 or so city.

 

My truck was just a little above E and I put $40 in which was about 10.8 gallons and it went to half of a tank and I have a 30 gal tank.... So I'm guessing even if ur at E then there's a gallon or 2 left in the tank

 

not burst any bubble, but the gas pump may have been shutting off early, and with the small amount you are talking about, the gauge would show full even if you were 2 gallons shy of normal full. Only way to know will be whether you see the opposite next time(lower than normal MPG)

 

of it could be like everyother ford, where the gas gauge is inacurate as all crap haha, mine finaly started going bad, i can fill my tank from 1/4 tank to full and it will say half tank till i park on a level spot and turn it off for 5 minutes.

 

Well mystery solved I guess. When I went out for lunch today I noticed the gauge was just a tick off the full mark. So I went to another station and let it fill up and got the other 3.5 gallons. I guess the other pump just clicked off too soon.

Damn, I was hoping I either got that 3 gallons for free or really got 18 MPG lol.

 

I took a 6 hour trip this pass weekend, 95% highway driving at 65+ mph and my truck averaged 17mpg every tank. I was stoked. Thats with an Edge programmer on economy, single flowmaster and a K&N.

 

Not bad. Here's my findings on a trip to Louisville.
https://www.f150forum.com/f4/mpg-report-89191/