Look Here A basic summary (in my view) of what's there would be something like:
1. If you don't buy gas for 3 days then buy it the fourth, you haven't had any effect. You think oil cartels will notice if the little guys sell the gas on Mon instead of Fri, Sat, and Sun? They've already sold it.
2. If you're pissed off about prices, why not hurt the guy at your local gas station who has already purchased the gas? It's the good old "We can't get to the people responsible, let's just beat up somebody" philosophy.
3. People in North America are already getting cheaper gas than people in other non-oil-exporting places.

The only effective thing would be to use less gas - not for 3 days, but for good.