More Perspectives on the Elusive Fuel Gauge Accuracy...

If your Prius is 'forgetting' settings, always suspect that your 12 volt battery is dying.


Somewhat on topic, I use this strategy:

Alone in the car, I get gas at one pip.
With my wife, we get gas at two pips.
Driving my Mother in Law? I get gas at three pips.

Sometimes, running out of gas could haunt you for years.

 

The Prius fuel gauge, commonly called the GuessGauge, does not reset unless you do a fill of about 4 gallons or more. A small fill gives a highly variable reading for MPGs so average your readings over several fills (add up the miles driven over the set of fills and divide by the total number of gallons) to get a more accurate estimate for MPG.

JeffD

 

Can you tell us how many pips were showing on the gauge after you "filled up". Are you saying that yours dropped from around 10 pips down to just 1 pip in 82 miles?