 This was because the 'Big Three' auto makers (General Motors, Ford, and Chrysler) did not have competitive cars at the time and were trounced in the fuel efficiency rankings until they introduced smaller platforms (GM "X" body, Ford Falcon, Chrysler A platform).Automakers tried to "prepare" their cars to achieve better results.An example was to use lightweight motor oil during the allowable "break-in" period "to promote faster wear and loosen the engines up quickly."