GM also said it was helped by heavy advertising on the Olympics and a full month of a money-back guarantee program for Chevrolets.

Industry analysts say U.S. auto sales are likely to keep the economy going even as it struggles to grow. The economy expanded at a tepid 1.7 percent annual rate from April through June. On Friday, Chairman Ben Bernanke made clear that the Federal Reserve will do more to boost the economy because of high unemployment and a recovery that remains "far from satisfactory." [...]

Honda and Toyota once again are expected to lead the way in sales increases. Last year at this time their dealers had few models to sell because a March earthquake in Japan hobbled their factories. This year they're back to full supplies.

Sales started the year strong, backed off a little in May, but came back during the summer. Schuster expects to end the year at 14.3 million, more than 1.5 million above last year. Sales hit a recent high of 17 million in 2005. The bottomed at a 30-year low of 10.4 million during the recession in 2009.