hmm, interesting. I might have to try out that acetone trick. Seems it was the most affective.
Plus i always thought it took more gas to turn your vehicle on after turning your car off at a light than it would to just put it into neutral.
Complete vaporization of fuel is far from perfect in today's cars and trucks. A certain amount of residual fuel in most engines remains liquid in the hot chamber. In order to be fully combusted, the fuel must be fully vaporized. Surface tension presents an obstacle to vaporization.
For instance the energy barrier from surface tension can sometimes force water to reach 300 degrees Fahrenheit before it vaporizes. Similarly with gasoline. Acetone drastically reduces the surface tension. Most fuel molecules are sluggish with respect to their natural frequency. Acetone has an inherent molecular vibration that "stirs up" the fuel molecules, to break the surface tension.
This results in a more complete vaporization with other factors remaining the same. More complete vaporization means less wasted fuel, hence the increased gas mileage from the increased thermal efficiency.