I have a new RX 400h (2008) and have been tracking mileage in the database. I've been entering the average MPG from the computer display. It took me a while to figure out how to reset the computer, so the first few tanks were actually reporting the running average for those tanks. However, for the last two tanks, I have reset the average MPG at the start of the tank.

At the end of the tank, when I fill up, I note the mileage for the tank from the Trip Odometer (I reset every tank) and also note the MPG average from the computer. Just as a sanity check, I also did the manual calculation of the Trip Odometer miles divided by the number of gallons that I put in. And I get a very different number than the computer! The MPG that I calculate is much lower...

Anyone experienced similar results?

I know that the variation in the shutoff point of the gas pump can cause some variability in how much gas goes in before the tank is "full". But I'm seeing around 1.2 gallons of variation, so I'm not sure if that would be due to the pump variability.

Thanks.

John