prius probed for engine stalls

FRANCISCO (MarketWatch) - Federal regulators on Wednesdayofficially opened an investigation into the red-hot Toyota Prius,responding to complaints alleging the cars' hybrid engine stalled intraffic. The National Highway Traffic Safety Administration said it received 33 reports of the gas-electric hybrid shutting down without warning typically at speed between 35 mph and 65 mph. The investigation covers about 75,000 vehicles.

Some of the complaints indicate that the vehicle was operated in electric mode for awhile after the gas engine stalled, NHTSA said. In at least half the cases, the car wouldn't restart and had to be towed.

Published reports detailing the potential problem first surfaced earlier this month, but NHTSA, while looking into the complaints, had yet to formalize an investigation until now.

There have been no reported cases of injuries.

The Toyota Prius currently dominates the competition, making up 64% of the overall hybrid market in 2004. Prius sales tripled in April to

11,345, moving towards the company's target of 300,000 a year.

Toyota previously pegged its long range annual forecast at 1 million hybrid vehicles.

Last month, Toyota announced one of its biggest ever recalls with

790,000 trucks and sport utility vehicles being called back to shops due to problems with the front suspension. See full story.

U.S.-listed shares of Toyota Motor (TM: news, chart, profile) added 1% to $72.44 in early trading.