Emission regulations became strict and cars were required to have catalytic converters. Seat belt laws were enforced. There are massive car recalls. The national speed limit is reduced to 55 mph. The big American cars and the American car industry in general suffer while the gas efficient and more reliable foreign cars are in great demand.
Japanese brands take much of the American car market leaving American car makers hurting.
During the 1980's gas prices stabilized and the economy improved. Chevy Cavalier and Ford Escort are competitive with foreign imports. Plymouth and Dodge Mini Vans and Ford Taurus are hot vehicles for families. K-cars bring Chrysler back. GM has its problems but starts to solve them.