Hi Texashchman:

___Always from the odometer and the pump as this is an actual value over time with actual miles traveled over actual gallons purchased. I do keep track of the FCD in my own spreadsheet and it matches almost dead on for lmpg but on a tank to tank, the FCD can display as much as 3% lower then actual calculated on the real high mileage tanks with the Insight I pilot. Not including the 3 or so times I was able to fill the Vapor recovery HW of course

___As a suggestion in case you do not keep your own spreadsheet, why not add a comment or two in the Notes area? Consider what was displayed on your FCD, your actual miles driven / gallons purchased = mile per gallon, traffic conditions, links to other threads about that tank, etc. I add all kinds of notes myself as it can only help others looking at your tank to tank data get a much better feel as to what you are actually receiving over time.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net