If you can't produce enough gasoline then the old "supply and demand" scenerio kicks in and the price goes up. 

Yep and this is a direct effect from the lack of building new refineries.  The EPA requires different grades of gas for summer use.  Many refineries were not built for this type of consistent change and the retofitting is a huge expense.  So, the oil companies take their time to make the change over in the late spring and we usually see higher gas prices going into the summer vacation season just because there is  a lack of refinery capacity....less supply, more demand = higher prices.

John