Most upbeat were executives from General Motors Corp., which posted a 20.3 percent sales decline from a year ago, but a 31 percent improvement over July's dismal totals.

Much of the gain came from offering all buyers employee discounts on many models, but Mark LaNeve, GM's vice president of North American sales, said there was hope that June and July were the trough for U.S. sales.

Chrysler L.L.C. said its U.S. sales fell more than 34 percent in August, while Ford Motor Co. reported a 26.5 percent decline. Toyota Motor Corp.'s sales dipped 9.4 percent, and Honda Motor Co. Ltd. reported a 7.3 percent slide.

Nissan Motor Co. Ltd. was the only major automaker to report an increase over August 2007: Its sales climbed 13.6 percent.

Even though most automakers said their sales dropped, many predicted the overall market would be up substantially over July, the worst month for U.S. sales in 16 years.

They also said lower fuel prices were starting to ease consumers' minds, with the market shifting a little bit back toward trucks and sport-utility vehicles, which increased their percentage share of the market.

Company officials also said consumer sentiment was improving, housing-price declines and manufacturing production are stabilizing, and exports continue to be strong.

But the companies tempered their remarks by saying they will face challenging conditions for the rest of this year and even into 2009.

While Chrysler had a huge decline from the year-ago period, it showed a 12.3 percent gain over July.

But Ford sales dropped compared with July, due in part to its continuing plan to reduce low-profit sales to rental-car companies and other fleet buyers, said George Pipas, Ford's top sales analyst.

Ford also does not expect a sales rebound in the second half of the year. It said yesterday that it planned to cut 50,000 more vehicles from its production plan in the second half of the year, reducing its output to 890,000 in the last six months of 2008.

There were some bright spots for Ford. Sales of its Focus small car were up 23 percent in August, while Escape small SUV sales rose 17 percent compared with the same month a year ago.

Ford and GM reported big inventory reductions in August as they switched to the 2009 model year.

Toyota said its car sales were down 3.4 percent from August 2007, and trucks were down 17.6 percent. Sales of the tiny Yaris were up more than 20 percent for the month, while the Camry midsize sedan had sales growth of 3.3 percent, the company said.