The price of a gallon of gasoline moved sharply higher this week as uncertainties about supplies caused speculators to bid up the prices of crude oil and gasoline futures, according to AAA Texas' Weekend Gas Watch.

The average price of regular self-serve in Texas jumped 10.3 cents per gallon to $2.832, which is 70.9 cents higher than the price last year. Dallas motorists are paying the highest prices at $2.899 a gallon - a weekly increase of 8.9 cents. The lowest average can be found in San Antonio at $2.764 a gallon, up 11.2 cents since last week.

"Investors have been climbing a wall of worry because the nation's inventories of gasoline have declined in recent weeks. Some refineries are switching to a formula of gas that requires ethanol instead of MTBE and there have been spot shortages of ethanol," said Paul Gonzales, spokesperson for AAA Texas. "Within 3-4 weeks, refineries completing their transition should be at full production and as many as one million additional barrels of gasoline per day will enter the nation's supply stream and prices should decline."

The national average for regular self-serve gasoline is $2.825 a gallon - 10.8 cents higher than a week ago.