there is a function call "fuel per hour" or "consumption per hour" that shows an instant continuous reading.
So one day you can coast down a regular hill and stay in gear, and the next day you can coast the same hill in neutral.
The you can see the difference.
Remember, the gauge is giving you a gallon/hour reading so you have to divide by the guestimate of the number of minutes you actually coast.
God Luck!
(ps you can buy a scangauge from this site!!
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