[azraelswrd]

I remember reading some posts on CleanMPG that Toyota built-in MPG meters are notorious for being too optimistic (ie higher MPG than it should be). Not sure what would account for these discrepancies but this is why nothing beats the odometer-tank fill method of MPG tracking.

But at least you know now that the meter is higher than it should be so you have a higher "target" MPG to aim for and stay at. This is also why I keep a little sheet with estimated miles at 1/4, 1/2 and 3/4 empty on my tank and their respective MPG values. That way I can see if my scangauge is close or off from what my fuel gauge/odometer is telling me where I should be at.

For example, with a half empty tank (5.5gal), I expect at least 220 miles on the odometer for a ratio of 40 MPG/tank.