Auto sales continued their downward spiral in September, as consumers struggled with both high gas prices and tightening credit conditions.

Ford ( F) said Wednesday that total vehicle sales fell 33.8% last month to 116,734 vehicles, with a steep drop coming in sports utility vehicles. Analysts had expected Ford to report a 25% decline in auto sales.

Ford said that September marked the lowest sales month for the automaker this year. September had 24 selling days, one less than the same month a year ago.

"Consumers and businesses are in a very fragile place," said Jim Farley, Ford group vice president of marketing and communications. "An already weak economy compounded by very tight credit conditions has created an atmosphere of caution."

"The automakers and dealers tell us the credit crunch is the number one reason for the drop in sales. People want to buy cars but can't get financing," said Michelle Krebs, senior editor of Edmunds.com's AutoObserver, in a statement. "Plus consumer confidence, which is waning in light of the near-collapse of the financial sector, is another critical factor that just isn't there."

Toyota ( TM) also reported a greater-than-expected decline in September sales. The automaker reported a 29.5% slide to 144,260 vehicles, compared with expectations of a 17.5% fall.

General Motors ( GM), meanwhile, said sales slumped 15.8% from a year ago to 284,300 vehicles, which is better than most analysts had expected. GM North America said its fourth-quarter production forecast remains at 875,000 vehicles which is down about 16% compared with the same quarter a year earlier.

"September marked the second consecutive month where GM performed extremely well in tough market conditions," said Mark LaNeve, vice president of GM North America vehicle sales, service and marketing, in a statement. "We again gained retail share and our total market share looks to be above 27% for the month without an increase in incentives."

Shares of Ford were tumbling 64 cents, or 12.3%, to $4.56, and Toyota was losing $1.44, or 1.7%, to $84.36. GM was lower by 4 cents, or 0.4%, at $9.41.