i generally run it to the nearest dollar which is not really topping off since i could probably run another gallon or two in there. these days, rounding off to the nearest dollar is less than ¼ gallon
Your judgemental assumption is wrong. I have never taken that long to top-off my tank with someone waiting behind me in line. There are plenty of pumps with no lines near me and courtesy is more important to me than your comment implies.
It's bad in any car, because topping off can permanently damage the evaporative emissions system, which may not harm your car, but is bad for the air we breathe. Tank-to-tank differences even out over the course of a few fill ups. If you look at my two-year Fuelly records, you can see this is so, a slightly low mileage tank is typically followed by a higher mileage tank.
While I will agree it will all even out, if you are testing various Hypermiling techniques it is imperative that you have accurate feedback. Once the learning experience is over then exact fill up information is unnecessary.
I have filled up to the top of the filler neck a few times and can report the tank will hold another 2 gallons of gas from the first click from the auto shutoff on slow speed. That is a minimum of at least 90 miles extra per tank. I don't normally fill up to the top of the filler neck because I live in Oregon and it is a violation to pump you own gas into your car. Yes a violation of law, I believe New Jersey has the same law. I read the 2010 owners manual and there is nothing that states not to fillup your tank to the maximum amount Maybe the 2011 and 2012 owners manuals have that now listed.
My statement wasn't directed at you and you may not do it; however, other people do it. I actually waited in line behind a Gen II owner who took that long to top off and kept staring at me. Extremely disrespectful, although he was probably jealous of my Gen III.
Yes, there's a big sidebar of cautions titled, "When refueling the vehicle," and one of the cautions is, "Stop filling the tank when the fuel nozzle automatically clicks off." Coming Soon: 2012 Plug-in Prius
