The global economic slump has hit U.S. automakers hard. Fearful about their jobs, many American consumers are in no mood to buy even a utilitarian family car, much less a luxury model that can run $40,000. Consumers in Europe and Japan are also steering clear of auto dealerships. But there are a few bright spots in this otherwise dismal picture. The Big Three U.S. automakers have made big improvements, and buyers have noticed, after more than a decade of shunning Detroit in favor of Japanese products. American consumers who are in a car- buying mood increasingly are buying American. They seem to be coming back to U.S. products to get what they abandoned them for in the 1980s: reliability, selection and price.