This is just dumb. First of all, Chevron wouldn't even notice if a bunch of disaffected forum nerds didn't buy their gasoline. Look at the total number of active car people that post on forums. Maybe.... 100,000 for all models? I bet not that much. Now how many millions of cars are on the road? So, fewer than one percent of the normal Chevron buyers buy somewhere else for a while.
They would never even notice.
If you REALLY want to catch the oil companies' attention, start carpooling or usuing public transportation. Start voting for candidates with strong platforms for the development of more efficient public transportation... or even become such a candidate. Then, maybe you'll make a difference. But face the facts; if people can afford higher gas prices, they may grumble a bit, but most Americans are just plain too lazy to do anything about it.
Circulating an email or making a post to an internet forum is not activism, folks.