So I filled up my 2012 Prius yesterday. I had about 20 miles left before empty according to the meter on the dash. Usually when I fill up, the meter will say I can drive 615 miles before another fill up, but yesterday the meter read 655 miles before another fill up. Is my meter faulty? I was thinking the weather may have had something to do with it because it was 106 degrees F when I filled up. Usually I fill up in 92 degree F weather. Anyone else experiencing this?
The miles before fill up is calculated based on your past fuel consumption. If you had recently gotten better fuel economy, then the miles before fill up number would be higher.
It probably means that you drove with better mpg on the latest tank, and it used this improvement to predict more miles for the next tank. But it could also mean that the fuel nozzle cut off late, and this refill simply went higher than normal. Don't overthink this, or put too much faith in the displayed number. It is an estimate based on a number of assumptions. But driving conditions continually change to no longer match those assumptions, so the forecast point of 'empty' also changes. Note also that the 'empty' point has some built in safety or reserve margin. If you wish to dip into this reserve, other threads have estimates of the likely size, but your particular fuel gauge will have its own variance.
