Should the United States raise the CAFE (corporate average fuel efficiency) standard? (read below)?

United States Automakers must meet a standard for Cooperate Average Fuel Efficiency (CAFE.) This means that the average miles per gallon achieved by all models of a companies American made car must meet a government mandated level. If they do not the company must pay a stiff fine. Should the United States raise the CAFE standard to conserve fuel and reduce air pollution even if the results could (and in most cases probably will) result in loss of American job and in turn have a negative impact on our countries economy?