DETROIT—U.S. auto safety regulators have stepped up a series of investigations into engine fires that have plagued Hyundai and Kia vehicles for more than six years.
The National Highway Traffic Safety Administration says a new engineering analysis investigation covers more than 3 million vehicles from the 2011 through 2016 model years. The agency has received 161 complaints of engine fires, some of which occurred in vehicles that had already been recalled.
