Automakers have slashed their second-quarter North American production plans by 350,000 to 400,000 units since February, to about 3 million, forecasters say.
"And we expect to see worse as we get further into the second quarter," said Jeff Schuster, top vehicle forecaster for J.D. Power and Associates. "We definitely see the potential for more cutbacks to come."
Since mid-February, Schuster cut his second-quarter production forecast 350,000 units to 3 million light vehicles. And IHS Automotive sliced its forecast 400,000, or 12 percent, to just under 3 million.
"This is purely because of the Japan parts shortage," Schuster said. "U.S. consumer demand is still strong, stronger than expected."
None of the North American production cutbacks are because of the rising price of gasoline, Schuster said. Fuel prices could change production plans for larger vehicles later in the year if they continue to rise, "but it hasn't shown up in second-quarter production schedules yet," he said.
George Magliano, IHS senior automotive economist, disagreed. "The parts shortage is the immediate problem, but fuel prices are a longer term problem" that will soften U.S. sales and North American production in the second half, he said.
Schuster said the lower second-quarter North American output -- combined with even larger production cutbacks in Japan after the March 11 earthquake -- will create U.S. shortages of small and mid-sized cars.
Japanese automakers are the most affected. Since February, Toyota, Honda and Nissan have cut almost 200,000 vehicles, or 20 percent, from their North American build schedules, IHS said. But the Detroit 3 also shed 191,000 units, about 9 percent, from their second-quarter North American output plans.
So instead of rising 11 percent from the second quarter of 2010, output this quarter will fall 3 percent, IHS said.
If North American factories resume normal production by July, automakers will make up the lost production by year end, Schuster said. He has kept his 2011 production forecast at 12.9 million units and his U.S. full-year sales forecast at 13 million.
The IHS full-year production forecast is 13.1 million, but last month it cut its 2011 U.S. sales forecast to 12.9 million from 13.3 million.
Magliano said: "That's down 200,000 units because of the parts shortage and about 150,000 because of oil prices."