MPG Display and Actual usage don't match

Yeah, pretty much everyone. The numbers you quote are actually pretty close. My error (vs displayed) with around 3 years calc'd is 7-8 percent.

 

Just about everyone in this very long thread: calculated vs. computer MPG - Please post your results

 

mine is just the opposite, however, in my gen II, it was reverse.

 

Same here. Shame Toyota cannot get it right. I use fuelly

 

I just drive the car. No hypermileing. The car was bought to be a utilitarian vehicle that gets me to where I need to go with minimum cost and minimum fuss. Do I care about the last 2%? Not when it is getting twice what the SUV is replaced got. I accept that temperature sensors around the home may not perfectly match (though I replaced one that was off by 50% today), no speedometer ever matched the GPS, no GPS matches another GPS, and all mileage claims or displays are suspect. I believe fuelly only to the extent the odometer is accurate. But as long as they are all close enough to give me a relative and approximate value on which I should base my actions....