Chuckanut
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
I've heard (not confirmed) that the relative price of diesel vs gasoline is not so tightly linked to the cost of production as it is to supply and demand.
Economics 101 - Price is a function of supply and demand.
Cost of production will certainly affect supply, of course. Just as substitutes affect demand for a product.