DETROIT — U.S. sales of cars and light trucks fell to just under 746,000 in September, down 41 percent from August.

Last month's slump brings car and truck makers back to earth following a heady August when automakers got a brief lift from Cash for Clunkers. Big rebates lured buyers who may have waited to go to dealerships. The question remains whether dealers can lure buyers back and help the industry recover this year. October traditionally has slow sales.