SAN FRANCISCO – Ford Motor Co., General Motors Corp. and Chrysler LLC on Wednesday posted double-digit August sales declines and offered little hope for relief in the coming months with demand for new vehicles sapped by still-high gas prices, the housing slump and tighter credit.

Toyota Motor Corp. fared better as sales fell 9.4 percent to 211,533 cars and trucks. Nissan Motors bucked the trend with improved sales.

Chrysler took the biggest hit, posting a drop of 34 percent to 110,235 vehicles from a year ago. Car sales plunged 39 percent to 26,016 vehicles and truck sales fell 33 percent to 84,219 vehicles.

The only models that saw any improvement from a year ago were Chrysler’s Town & Country minivan, up 15 percent, and Charger sedan, up 3 percent.

“Automakers, especially the domestics, are trying to realign their supply better with demand and we’re seeing that having a big impact on overall sales,” Edmunds.com analyst Jesse Toprak said, adding that a move away from rental car sales is also a major headwind.

For Ford, the pullback was even more severe than Wall Street had expected. Analysts polled by Thomson Reuters were looking for a slip of 20.9 percent. Ford sales dropped 26.6 percent.

Ford’s truck side, down 32.3 percent, was again to blame – with the flagship F-Series pickup, once the best-selling vehicle in the country, dropping 41.6 percent.

Ford, Lincoln and Mercury car sales fell 8.9 percent while crossovers dipped 1.3 percent.

Volvo, the lone remaining European luxury brand, saw sales retreat 48.8 percent to 4,669 vehicles. Earlier this week, Ford named a new chief executive at Volvo and reaffirmed its intention to keep the marque.

Overall, the Dearborn, Mich.-based automaker sold 155,690 cars and trucks, down from 212,120 a year earlier.

“We expect the second half of 2008 will be more challenging than the first half, as weak economic conditions and the consumer-credit crunch continues,” said Jim Farley, vice president of Ford marketing and communications, in a statement.

Ford also cut its second-half production plans to 890,000 cars and trucks, down from a prior target of 940,000, citing lower sales to daily rental companies, the transfer of production from one plant to another and a lower sales outlook for the industry.

The company said that it sees industry vehicle sales for the year coming in at the low end of its range of 14 million to 14.5 million cars and trucks.

GM’s August U.S. sales fell 20.3 percent to 307,285 light vehicles, topping analysts’ targets for a 28.8 percent decline as the automaker’s revival of the employee-pricing deals helped bring buyers to showrooms. GM also said that it will extend its promotion through Sept. 30 and add 2009 models to the sale due to “ongoing customer and dealer demand.”

Still, car sales slid 13.9 percent and light-truck sales fell 24.1 percent. But the results are facing a tough comparison with a strong showing in August 2007 and mark the best month so far this year.

“With the recent moderation in fuel prices, we’re seeing some relaxation of pent-up demand in pickups and utilities,” said Mark LaNeve, head of GM sales and marketing.

By brand, Hummer, which is currently being shopped around, posted a 62 percent plunge in sales to just 2,160 vehicles. Saab sales were chopped in half while Pontiac dropped 38.2 percent.

Saturn turned in the best performance, but still saw sales fall 3.5 percent to 20,385 vehicles.

GM said it plans to produce 920,000 cars and trucks in the third quarter, down 10 percent from the amount rolled out in the same quarter a year ago. GM set its fourth-quarter production target at 875,000 cars and trucks, down 16 percent from a year earlier.

“It’s really too early for anyone to declare victory on the economy in terms of it having turned the corner,” GM sales analyst Mike DiGiovanni said in a conference call. “But it appears to us that there’s a number of positive developments that indicate we may be at or near the bottom of the economic trough …”

In keeping with the industry trend, Toyota’s trucks and SUVs bogged down sales results. The light-truck side fell 16.4 percent to 81,911 vehicles while cars slipped 4.3 percent to 129,622. Increased sales for the subcompact Yaris and the Camry sedan helped offset declines for the Corolla and Avalon.

The luxury Lexus division also suffered, with sales falling 9.1 percent to 29,281 cars and trucks.

Honda Motor Co. reported a 7.3 percent decline to 146,855 vehicles. Total car sales fell 5.1 percent to 86,827 vehicles and truck sales dropped 10.3 percent to 60,028 from a year ago

Nissan managed to keep from getting dragged down with the competition as U.S. vehicle sales rose 13.6 percent to 108,493 units from 95,527 a year ago.

In another stark contrast to industry trends, Nissan’s car sales slid 0.8 percent to 56,476 while truck sales rose 34.8 percent to 52,017 units.

The auto industry, as a whole, spent an average of $2,642 per vehicle in incentives last month, up 7 percent from a year ago but down slightly from July, according to car-buying research Web site Edmunds.com.

Chrysler, bogged down by its truck- and SUV-heavy lineup, led the way with $4,366 per vehicle, up from $3,769 a year ago.

GM spent $3,865 per vehicle, up from last year but actually lower than July despite its latest employee-discounting promotion.

“Because the program required dealers to participate and subsidize part of the offer, the result was a net decrease in GM’s overall incentive costs” from the previous month, Edmunds.com analyst Jesse Toprak said.

As for the Japanese manufacturers, Toyota Motor Corp. ramped up its spending to $1,398 per vehicle from $887 a year ago, while Honda and Nissan, both much more reliant on smaller cars, only fractionally raised their incentives for the month.