National on-highway diesel prices dropped six-tenths of a cent from last week to $3.862, following a rise of more than 4 cents the week previous.

Diesel fell modestly in most regions last week, the exceptions being the Rocky Mountains, the West Coast and California. California remained the most expensive at $4.067. The Gulf Coast, at $3.790, was again the cheapest.

Nationally, diesel is up 91.9 cents over last year.

Oil prices gained on Monday after falling early in the day amid fears of Greek debt default and an imperiled Euro. Light sweet crude for October delivery picked up 1.1%, settling at $88.19. U.S. crude is down 4.4% year-to-date.

The Organization of Petroleum Exporting Countries reported Monday that it expects demand growth to be 150,000 barrels per day shorter than earlier forecasts. The cartel scaled back its production outlook correspondingly.

Markets across the board, oil included, have been all over the place recently as a looming financial crisis darkens Europe and threatens the very existence of the Euro. Germany, the anchoring Euro-zone economy and home to European Central Bank, may or may not shoulder the weight of the seriously faltering states Greece and Ireland, and the questionably stable Italy and Spain. A decision in the negative could potentially plunge the world into a second global recession.