DETROIT — Strong demand for pickups fueled a big jump in U.S. auto sales last month. GM’s August U.S. sales rose 10 percent compared with a year earlier, while Ford’s rose 13 percent and Chrysler’s 14 percent. Americans flowed steadily into auto dealer showrooms, ignoring high gas prices, hot temperatures, poor economic numbers and even a hurricane. Model-year closeouts and appealing new cars made it even easier for buyers to replace rapidly aging vehicles last month. Pickup trucks, traditionally the top sellers in the U.S., seemed to drive much of the business. Sales of Ford’s F-Series trucks rose 19 percent, while Chrysler’s Ram jumped by the same amount. GM’s Chevrolet Silverado, among the oldest trucks in the market, saw a 4-percent sales increase. Toyota and Volkswagen did well in car sales.
