$4 gas could tank Big 3 sales

Auto executives were upbeat at this year's Detroit auto show, buoyed by a sales recovery that's gaining momentum, rising profits and renewed consumer interest in American cars and trucks.

But a rise in gas prices is casting a shadow across the industry's otherwise sunny outlook.

Prices at the pump have climbed above the $3-a-gallon level that catches drivers' notice, and Detroit's automakers are more exposed to rising gas prices than most of their rivals.

General Motors Corp., Ford Motor Co. and Chrysler Group LLC displayed an impressive lineup of small and fuel-efficient cars at the North American International Auto Show. But they still generate their biggest profits from light truck sales.

The U.S. automakers benefited last year from a rebound in truck and SUV sales, underpinned by stable gas prices. Two years earlier, truck sales had collapsed when gas prices surged above $4 a gallon.