To accurately measure MPG when should I fill back up.

[Pavel Olavich]

Originally Posted by jamal1984

my fucking yaris can't never get to 30 mpg. it's really suck

Well then pull your leg out of the throttle body, for god's sake!

Seriously, your low MPG is because you're not driving it correctly for high MPG, or there is something wrong with your car, or both. Get the car checked, and get the driver (you) to go to gassavers.org for high MPG driving tips.

To the original poster, to calculate MPG, you can fill up ANYTIME...to calculate the MPG, but know this, that the calculated MPG is an AVERAGE of the gas that your car has consumed since the last fill up, so the closer to empty you get the more accuarate the calculated average MPG will be. You can wait until the car is nearly empty, or half empty or 1/8th empty, but regardless of this, the calculated MPG is an average over the consumed gas.

Get yourself one of these: www.scangauge.com and you can get the instantaneous MPG, average MPG, tank MPG, trip MPG, plus 10+ more parameter values that your car provides this device via a port that all our cars have under the dash.....I have the ScanGauge II and I love this think...when calibrated properly it is dead accurate, and it even shows RPM, water/intake air tempurature, plus many more values...