Falling gas mileage

It's true. With the Prius length does matter. No matter how well you use it (the Prius, that is), if you have a short commute you'll notice a big hit. Getting an engine block heater can help.

One thing that I've noticed about the fueling issue in cold weather is that the pump itself seems to play a major role. I first noticed this on a day where the outside temp was in the high 20's. It took me an age and a day to put 8 gallons in the tank. And that was with the pump set on the slow setting. Earlier this week, with the temp at 0 I was able to easily fill up with 7.6 gal (US) without the autoshut constantly "clicking out". In fact, it didn't click out at all until finished. Of course the bladder had contracted so I ended up with a short tank. I haven't done this enough to be sure but the two data points I have suggest something is up. Maybe by the end of the season I'll be convinced one way or the other. The problem is that even with the crappy winter fuel economy I still don't fill the car up very often.