Business Notes AUTOMOBILES

Those big cars -- and their thirsty engines -- that Americans have once again come to love blew a tire last week, when the Bush Administration approved tougher fuel-efficiency standards for all automobiles sold in the U.S. As of 1990, all cars produced by each auto company must average 27.5 m.p.g. of gas or the manufacturer will face stiff penalties. The Reagan Administration had relaxed the standard -- first established in the oil-shocked '70s -- to 26.5 m.p.g. for model-year 1989. But Transportation Secretary Samuel Skinner cited "economic security" in resisting Detroit's plea to maintain 26.5 m.p.g. for a longer period. "We are now importing a higher percentage of petroleum than we were in 1975," said Skinner. "We may very shortly be dependent on foreign sources for more than half of our oil."

General Motors, which expected its fleet to average 27 m.p.g. next year, criticized the decision, declaring that it will cost jobs to go that extra half-mile. Chrysler and Ford said they were prepared to meet the new requirements.