General Motors Co.'s U.S. sales rose 20 percent in September because of strong demand for full-size pickups and SUVs.
Pickup and SUV sales are generally stronger in the fall, and GM and other companies were offering promotions on trucks. GM truck sales climbed 34 percent from September of last year, a much stronger increase than cars, which rose 12 percent.
Sales across the industry are expected to have risen in September as more Japanese vehicles fill showrooms after months of earthquake-related shortages.
But analysts say the jump in sales could be short-lived because potential car buyers remain worried about the economy.
GM says sales of the Chevrolet Silverado, one of America's best-selling pickups, rose 36 percent, while sales of the Chevrolet Tahoe SUV rose 63 percent.
Chrysler reported a 27-percent jump in September sales.