i'm not that guy. I'm not going to ask about a gas tank that doesn't seem to hold its reported capacity... rather, i'd like to relate that our '04 has been consistently holding 8 gallons or less on fill-up. this has been the case even when the computer has asked us to add gas to the car and with the last 'pip' blinking however, yesterday we still had one pip and no warning, and had a 9.7 gallon fill-up. we were surprised to see such a high number at the pump, and we'll know at the end of this tank based on calculated mpg or the next fill if the tank has expanded or we just got robbed by the gas station.
In North America, the 2004 to 2009 Prius uses a rubber bladder inside the metal gas tank to reduce gas fumes. At different temperatures it will expand and contract differently. In colder weather you will seem to have a smaller tank, usually warmer weather allows it expand more. This makes it hard to guess when you will need gas again. My advice is to find a distance that always works and fill up then. I get gas once I go 400 miles.
Every once in awhile I also get a larger than normal fill-up. It never happens at my normal stations, so I suspect it is a combination of weather and a pump with different shut-off characteristics. Of course, as you mention, the station's pump may be cheating a bit as well. Tom
Do your pumps use the rubber cover thing from the neck of the pump to the tube? Only time I have had problems with weird fills is with those no vapour escaping ones and they fill less. Did you notice if your usual fill up locations have the rubber necking while your latest fill station did not?
As I said... I know about the bladder and am used to less than consistent fill-ups but this just exceeded all my previous fill-ups by well over a gallon. Generally I fill up at the local QT or Costco... This was a Circle K in a less savory part of town and it didn't seem to have the little escape valve or special rubber thing.
mabe the gas station is pumping air along with gas. cheating you out of your money! alot of low priced gas- gas stations do that! lure and hook i think! it hapens in greece alot!