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 units, with a steep drop coming in sports utility vehicles. 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."

Shares of Ford were lately falling 69 cents, or 13.3%, to $4.51.

"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."

Ford's rivals General Motors ( GM) and Toyota ( TM) are due to release monthly sales figures later Wednesday. Edmunds.com predicts GM sold 255,000 vehicles last month, down 23.9% compared to a year ago, and that Toyota will see a 17.5% decline.

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