U.S. automakers are set to get a break on some of the sweeping tariffs President Donald Trump is imposing. Yet even with the new waivers, the outlook for America's longest-lived carmakers remains cloudy, with General Motors saying Tuesday it was "reassessing" its earnings guidance in light of the uncertainty over the tariffs impact.

The proclamation came ahead of Trump's visit to Macomb County, home of many autoworkers, to mark his first 100 days in office.

A slower phase-in for tariffs on auto parts will give manufacturers more time to ramp up manufacturing in the United States. Some analysts warn the tariffs will still drive car prices up.