Was 100% manipulated. It has been documented and proven how.
1) Goldman Sachs, who has a loooong history of working with the gov't and whom many of current administration formerly worked, control the largest commodity index in the world. Back in August 06 they drastically reduced the weighting of unleaded gasoline futures in their index, causing a sharp selloff in gas. Why? - no comment from GS.
2) The crack spread, which is the difference between what it cost refiners to produce gasoline and what they sell it for, was also reduced to zero....exactly one week after G. Sachs did their thing. They were selling gas for zero proifit. An unpresedented move.