I have a 2005 Lariat F150 4X4 with the 5.4. I have about 6000 miles on it, with a K&N air filter and Gibson cat-back exhaust. I just filled my tank with the digial display saying that I got 12.1 MPG. I calculated it myself and I got 13.0. This is the first time I've even bothered to calculate it myself so I'm not sure if its a problem that gets improves or gets worse if I do more highway driving. Anybody else experienced this?

 

I have the the same config you have and 13 seems about right. Mileage for me averages about 12.5 to 14 mpg.

 

But is it normal for you to have the difference between indicated and actual mpg?

 

My computer said I was getting 12.6 mpg and when I did the math, Im really getting 14.5, go figure.

 

Does anyone know how the computer calculates the mileage?
I'm willing to bet the computer is more accurate than doing the math yourself.

 

I think the computers odd cause i mean just take the miles that you went and how many gallons you PUT in the truck and divide! how hard could that be?

 

The problem is that you dont know that the tank is filled to the exact same level as the previous fill up. That is where the manual calculations can be inaccurate. I would trust the computer calculations more than the manual calculations.

 

I wouldn't...

 

I'm with GB150 on this one...my math is good, but I imagine the computer knows how much fuel is being pumped thru the injectors vs how many miles the truck is driven...now it may well be an average, but a computers average is still better than the owners assumption of how much fuel he/she has put in per fill up..


R/
Craig

 

I would think if you know how much fuel your adding and what the tank actually holds and your driving habits you could probably get a pretty accurate estimate on MPG. NASCAR crew chiefs are usually pretty acurate with their math on calculating fuel milage and they don't use onboard computers. Hell just bring your trucks in for a round of wedge and a splash of fuel and go.

 

But even if you take into account +/- a couple tenths of a gallon for varying levels in the tank, I still get better gas milage the way I calculate vice my onboard computer.

 

Yeah, but you're young and not as smart as you think you are.

 

 

Go With the one that makes you feel better