DETROIT — Sales fell at General Motors, Toyota and Volkswagen in September, an odd month that appears likely to snap a 27-month streak of gains for the U.S. auto industry.
GM posted an 11 percent decline compared with a year ago as the company even reported falling sales of its redesigned full-size pickup trucks. Pickup truck sales have been a strong point for the industry as small businesses return to dealer showrooms. Volkswagen sales were off 12 percent, while Toyota sales were down 4 percent.
But Ford and Chrysler appeared to have outperformed the industry. Ford sales were up 6 percent, while sales at Chrysler rose 1 percent.
All automakers report U.S. sales on Tuesday. Chrysler and Ford officials joined many industry analysts in predicting that overall sales fell last month for the first time in more than two years. Analysts say a quirk in the calendar — not lower demand — is to blame.
Labor Day weekend is typically strong for U.S. auto sales, and this year was no exception. But because the holiday came early, the auto industry counted all of that weekend's sales in its August tallies. That means September's sales will be missing the usual holiday boost.
Analysts say all the factors that have been driving this year's strong car sales — including low interest rates, the improving economy and the need to replace aging vehicles — remain in place. They see a strong close to the year.
"The market continues to move at a very healthy pace," said Erich Merkle, Ford's top U.S. sales analyst.
September U.S. sales are expected to total around 1.1 million, according to auto shopping site Edmunds.com. That would be a 4 percent decrease from last September and a 24 percent decrease from the blistering pace in August, which was the best month in more than six years.
The U.S. government shutdown could be the wild card that cuts into sales for the remainder of the year, but Jim Lentz, Toyota's North American CEO, said the only way it would have an impact is if it causes credit to tighten.
At GM, sales of the redesigned Chevrolet Silverado pickup fell 11 percent, while the GMC Sierra dropped nearly 2 percent, reversing a recent trend and marking a contrast to GM's main rivals in the truck market.
Ford reported that sales of its top-selling F-Series pickups rose 10 percent. Chrysler was buoyed by the Ram pickup with sales up 8 percent.
Chrysler also said sales of the Jeep Grand Cherokee SUV increased 19 percent.
Ford was led by sales of its Fusion midsize sedan, which jumped 62 percent over last September, while the subcompact Fiesta posted nearly a 29 percent gain. But sales of the Escape SUV — one of Ford's best sellers — dropped 2 percent to 22,607, and Explorer SUV sales were up just 1.5 percent.
Bill Fay, the Toyota Division chief, said September was still a good month for the industry even though there were two fewer selling days than a year ago. "Industry fundamentals are strong as interest rates stay low and consumers remain confident," he said.
Volkswagen, which has struggled all year against strong 2012 numbers, had a poor month. Its top-seller, the Jetta small car, posted a nearly 10 percent sales decline.
Nissan also reported a sales drop, off nearly 6 percent from a year earlier. The Nissan Division's sales were off 6 percent, while the Infiniti luxury brand posted a 4 percent decline.