AP. The National Highway Traffic Safety Administration is beginning a preliminary investigation of the Toyota Prius based on reports of the engine stalling without warning. The initial probe will involve about 75,000 cars of the 2004-2005 model years.

The agency said it has received 33 complaints of alleged engine stalling. The majority of the complaints involved reports of the engine stalling at speeds of 35 miles per hour and 65 mph.

Toyota  said it was cooperating with NHTSA and would provide the agency with the complete results of its internal investigation.