The government is expanding its safety investigation into possible engine problems in 100,000 Volkswagen diesel cars.

The National Highway Traffic Safety Administration says it has received 160 complaints and field reports about engines stalling or losing power. The reports involve 2009 and 2010  Jettas and 2010 Golfs and Audi A3s with TDI clean diesel engines.

The safety agency says one minor crash reported has been related to a failure of the car’s high pressure fuel pump. About half of the reports describe engines stalling, with many at highway speeds in traffic.

Volkswagen told the government that the problem could be related to gasoline contamination from drivers pumping the wrong fuel. The investigation began in August.