GM Promises ‘Different Story’ in October After September Sales Slide

General Motors Co. blames a September sales free-fall on the comparison with an extraordinarily robust year-ago performance and let-down from the expiration of the U.S. government’s “Cash for Clunkers” incentive scheme.

GM delivered 155,711 vehicles in the month, a 47.1% plunge from like-2008’s 282,869 total, according to Ward’s data, which is adjusted for selling days – 25 in September vs. ...