on a quite similar topic to my last what do you think of this little article -
There are a few methods of saving on gas that ive learned while in class for truck driver training.
Progressive shifting: If you are driving a car with manual transmission, instead of winding the rpm's up and shifting gears while they fall, try and catch the next gear at a lower rpm, as low as the next gear will allow. A friend tried this in her car after learning about it. she got 32-33 miles per gallon instead of her usual 28-30.
Timing: Fuel up between 2am and 10am, temperatures are colder, and with that, gas is slightly more condensed. Pumps measure volume, not density.
If the gas station you go to has above ground fuel tanks, do not buy gas there. The only reason for fuel to be stored above ground is so the sun can heat it and cause it to expand, giving you less than what you paid for.
Good advice or paranoia setting in?