General Motors said U.S. sales rose nearly 4% in September, boosted by incentives on its pickup trucks, while Ford Motor and ToyotaMotor posted declines.
GM said it sold 337,640 vehicles in the U.S. last month compared to 338,380 vehicles a year earlier.
Sales were adjusted for an extra selling day last September.
Ford Motor said U.S. sales fell 18.3% last month, hit by a decline in showroom sales.
The second-largest U.S. automaker sold 189,893 vehicles in September, down from 204,070 vehicles a year earlier. The percentage decrease in sales is adjusted based on the daily sales rate and reflects 25 selling days in September versus 26 in the same month last year.
Ford said retail, or showroom, sales fell 15%, while sales to car rental companies were down 62%.