After checking my mileage month by month for a year, my 2007 egg (white Prius) came in at 49.6 in Triad Area North Carolina. About 70 percent highway mileage. Has anyone checked gas mileage the old-fashioned way to see how accurate the electronic calculator is?
My MFD has been 3.5% optimistic relative to calculated mileage over the entire life of the car. You don't learn much from a single tank because the tank is so finicky about how much gas it will hold. I'm sufficiently picky that when I track mileage I record both, and the "official" mileage for a tank is the MFD mileage corrected down by the 3.5% difference. It takes the "bounce" out of the tank-to-tank variation that the stupid bladder induces. (Yeah, I'm a scream at parties. )
