Is there a way to adjust the gallons used calculation like you can with the mpg?

 

My truck doesn't have a 'gallons used' option that I can recall.
Where are you seeing the option to show how many gallons?

 

In the trip display

 

What are you trying to calibrate?

 

Here's mine.

 

My 2014 has that display. They don't include it on newer trucks and I'm not sure exactly when they changed it.

FWIW my trucks "GAL USED" display and "AVG MPG" display are so close to what I get with hand calculations that I've stopped doing hand calculations. Over the last 5 years and 95,000 miles the amount of gas I pump has always been within .2 or .3 gallons of what the display says and when I hand calculate fuel mileage I see the same. It has never been off by more than .5 mpg and usually much closer.

There is a way to change how fuel mileage is calculated, but I don't know how. Never felt the need to worry about it. But "gallons used" is going to be directly linked to "MPG". If you recalibrate one, the other should be recalibrated too.

 

Sorry. Didn't pay attention you have the XLT. I know engineering mode is used on lariat and got wrapped up in that thought.

Seems the gallons used would be modified the same as the MPG though. With my logic, if you were to use engineer mode to adjust the mpg based on your hand calculations, it would therefore say "you drove 100 miles and have achieved X MPG, you must have therefore used X gallons of gas. Not sure you can chagne the MPG rating to something very silly and have the gallons used remain accurate. Either the gallons used is a sensor in the tank reading tank pressure or it's based off of X miles with X mpg = x used.

 

That's what I would have thought too. My mpg's are right on but the gallons show less than it uses. Oh well.

 

By how much?
Is it insignificant enough that you really didn't put in a full 12 gallons at the pump because you're on an incline or the pump flowrate? 1/4 gallon or 6 gallons off?

 

It's probably by 4-5 gallons off for a 36 gal. tank.