How to Calculate MPG?

[Cecil_Stringer]

So what is the tried and true method of calculating MPG?

My intent is to figure out what MPG the truck is "really" getting (the on-board display shows ~16mpg).

The truck is a 2003 PSD with a Banks 6-Gun (set on "6"), intake & exhaust upgrades, 37" tires and 4.56 gears.

Thanks!

[Justin C.]

It's pretty simple. To start out you need to fill your truck up. Then zero off your mileage and then just drive the truck until it's ready to be filled up again. When you fill up, look at how many gallons it takes to get it back full, and divide that into how many miles you drove since the last time you filled up.

Justin

[MikeL46]

That assumes your speedo is accurate. If it is not, you will need some means to get miles traveled, maybe a gps? or a ScanGauge.

It's probably best to record each fillup - miles driven, gallons used, mpg, road conditions (Snow, mountains, headwind, etc.) so you can see if some conditions lower fuel mileage.

Don't be alarmed if one or two tanks read high or low. It could be as simple as using a pump with a different shutoff sensor. If one pump shuts off early, that tank will use less fuel and get higher mileage. The next tank you will be wondering why you just dropped 3mpg when it was the early shutoff on the previous tank that caused mor fuel on this fillup.

Mike

[OT]

CS...you may find a difference in calc.mpg depending on how you fill tank. As mentioned or fill till to you see solid fuel in filler neck. May take another 5gal.? (after auto.shutoff) before you see it.

On mine, calc.mpg filling into neck seem's more accurate.JMO! I only do once in awhile. In between auto.(1st)shutoff give's me good enough indication. If mpg lower than expected, then I do solid fuel check. Just a thought.