In response to distortions of story, Obama said it seems like certain people "take pride in being ignorant."  Enter Newt Gingrich and Sean Hannity:

GINGRICH: Well, I got a very funny e-mail from a retired military officer in Tampa who pointed out that most tire inflation is done at service stations and you pay for it. And it’s actually a higher profit margin than selling gasoline. So Sen. Obama was urging you to go out and enrich Big Oil by inflating your tires instead of buying gas.

Video here.  The tire inflation advice was not only a strategy to deprive BIG OIL of vast profits, but one to save you money on gas.  So the amount invested on tire pumping (50 cents) will save you much more in fuel efficiency (with all of the accompanying benefits, such as depriving Big Oil of its profits, not filling the atmosphere with that much more carbon, etc.).  In case you're keeping score at home, this would amount to, I think, a fairly textbook case of suppressed evidence.