Fuel economy and fuel availability are very complex issues. The one simple thing I know that you can do is keep your tires properly inflated (check/adjust minimum of monthly and before any long or high speed trips or heavyly loaded use). Underinflated tires cost you money for fuel! Just read that clearing new crop land in the Amazon to make up for grain going to biofuel is now accounting for near 25% of the global warming. Unintended consiquences!!