CBS/AP) "A Prius? And what's going on? Is your accelerator stuck?"

That was the response from a Southern California 911 dispatcher after an apparently terrified man on a San Diego highway called for help from his out-of-control car.

"I tried to pull it back - it won't pull back," driver James Sikes says, his voice quivering in released audio of the call. "I tried to push on the brakes."

Sikes tells the dispatcher that he is going "eighty-something."

With the help of a California Highway Patrolman, Sikes was able to come safely to a stop, but the incident is more tarnish on Toyota's rapidly deteriorating reputation.

Sikes said that the incident Monday occurred just two weeks after he had taken the vehicle in to an El Cajon dealership for repairs after receiving a recall notice, but he was turned away.

"I gave them my recall notice and they handed it back and said I'm not on the recall list," Sikes said.

In fact, Toyota issued a recall for its Prius hybrid - the same model involved in Monday's incident in November but has yet to send official notices to all vehicle owners.

Toyota spokesman Brian Lyons told CBS Radio News that the automaker would notify owners of the recall "soon," but a Wall Street Journal report ($) quotes Lyons as saying Toyota "hasn't developed the remedy yet."

The recall, which covers 2004 to 2009 models, was issued Nov. 25 to ensure that faulty floor mats don't lock the cars' gas pedals in an open position.

In the interim, owners were advised to remove the floor mats from the driver side of their cars.

This latest incident comes as Toyota fired back at critics after weeks of apologies. The company is now using its own scientists to demonstrate that electronics are not the source of unintended acceleration, CBS News correspondent Ben Tracy reports.

Toyota has dispatched a field technical specialist to investigate the latest incident, according to a statement, Tracy reports.

Federal officials are sending two investigators to California to determine what caused Sikes' Prius to race out of control.

A spokeswoman for the U.S. Department of Transportation said Tuesday that the National Highway Traffic Safety Administration will try to determine what caused the incident.

Sikes sped along Interstate 8 for 20 minutes Monday before a Highway Patrol officer helped slow down the car.

CHP Officer Brian Pennings says the 2008 Prius was towed to a Toyota dealership in El Cajon - presumably for inspection.

Toyota has recalled some 8.5 million vehicles worldwide - more than 6 million in the United States - since last fall because of acceleration problems in multiple models and braking issues in the Prius.

On Monday, Sikes called 911 about 1:30 p.m. after accelerating to pass another vehicle on Interstate 8 near La Posta and finding that he could not control his car, the California Highway Patrol said.

"I pushed the gas pedal to pass a car and it did something kind of funny ... it jumped and it just stuck there," the 61-year-old driver said at a news conference.

"As it was going, I was trying the brakes ... it wasn't stopping, it wasn't doing anything and it just kept speeding up," Sikes said, adding he could smell the brakes burning he was pressing the pedal so hard.

A patrol car pulled alongside the Prius and officers told Sikes over a loudspeaker to push the brake pedal to the floor and apply the emergency brake.

"They also got it going on a steep upgrade," said Officer Jesse Udovich. "Between those three things, they got it to slow down."

After the car decelerated to about 50 mph, Sikes turned off the engine and coasted to a halt.

The officer then maneuvered his car in front of the Prius as a precautionary block, Udovich said.

Toyota owners have complained of their vehicles speeding out of control despite efforts to slow down, sometimes resulting in deadly crashes. The government has received complaints of 34 deaths linked to sudden acceleration of Toyota vehicles since 2000.

One of the crashes claimed the life of a CHP officer in August.

Off-duty CHP Officer Mark Saylor was killed along with his wife, her brother and the couple's daughter after their Lexus' accelerator got stuck in La Mesa.

The Toyota-manufactured loaner vehicle slammed into a sport utility vehicle at about 100 mph, careened off the freeway, hit an embankment, overturned and burst into flames.