Strong pickup demand 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. Most automakers reported strong gains as Americans flowed into dealer showrooms, drawn by model-year closeouts, low-interest financing and appealing new models. Analysts expect overall sales to rise around 20 percent when companies finish reported later Tuesday.