Federal safety officials from the National Highway Traffic Safety Administration are investigating consumer complaints that the Ford Freestyle crossover vehicles are unexpectedly lunging forward.

The safety agency has received 238 complaints from owners of 2005 to 2007 model-year Freestyles of unintended lunging at low speeds when the driver's foot isn't on the gas pedal.

Details of the investigation were posted during the weekend on NHTSA's website. The probe began May 11 and covers about 170,000 Freestyles. NHTSA will decide if a safety recall is necessary.

A Ford spokeswoman said the company is cooperating with NHTSA as it reviews the matter.

In the Ford recall posted at NHTSA's website yesterday, what consumers have described as a lunge, can be stopped by applying the brakes, but in some cases the vehicle has moved as much as 10 feet if the brake was not applied, lightly applied or applied late, the agency said, citing complaints.

Ford discontinued the Freestyle model in February 2009.