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Gas mileage

what is the best way to figure out your gas mileage.

miles driven divided by gallons filled

I know that. What i need to know is do you stop gasing up when the pump kicks back or do you top off the tank?

When the pump kicks off.each time and reset trip odometer.Just be consistant over three or more times to get a good idea of the mpg.Owner’s manual should give tips.

Not related to figuring mpg,stop at first click,do not top off.

I found not to trust the mpg computer on my crown vic. It consistently overstated my mpg. Ford trying to pull one over. Figure it by hand.

What i need to know is do you stop gasing up when the pump kicks back or do you top off the tank?

I suggest stopping at the first time it kicks off.  If you want to get more accurate numbers for a specific fill up, then make sure you use the same pump and that your car is in the same position at the pump (that is it is not tilted a little side to side or front to back.)  

Most modern cars have labels on them telling you not to top off the tank.  You should stop filling at the first time it clicks off.  Topping off the can can damage the system and you could find yourself buying a new charcoal canister and they are not cheap.

Butch, The More MPG Results You Average, The More Useful The Information.

Averaging 10 or 20 fill-ups will yield useful information and will make the “fill til over-flowing” vs. the “fill til click off” debate totally unnecessary. People are advised all the time on this site not to see how much gas they can pack into their tank. Doing so can force fuel into the evaporative system and even damage components.

Try and fill it about the same way each time and average several (many) fill-ups.

“I found not to trust the mpg computer on my crown vic. It consistently overstated my mpg. Ford trying to pull one over. Figure it by hand.”

Crown Vics don’t have a monopoly on untrustworthy mpg computers. I have found overly optimistic results too with mine. Why trust your trip odometer as well. If you suspect there is a problem and have a GPS you can use for distance, I would use it. I have a couple and find them much more consistent for speed and distance measurements in cars, bikes and boats.

After adjusting for your car and driving style they give a good, but not really good, approximation.  They are good for telling you that accelerating up a hill cost you and that letting up on the accelerator will save you fuel.  

You can use it to fine tune your driving style for the best mileage.

Thank you all for some good advice…Butch