My wife was driving at 40 miles per hour when the engine suddenly begain to over-rev, causing her to nearly lose control. The car quickly accelerated to 60 miles per hour. All this happened on a state hwy which had several "S" curves going downhill.

She was unable to shut engine down using either the power-button, nor could she shift out of drive.

Finally, after the road flattened out, she was able to bring the car to a stop. However, the hard braking resulted in a left, front disk brake fire. The fire was put out by a man who was alongside the road. He was able to run to his house for 2 fire extinguishers.

The event occured on Wisconsin state route 107, approximately 1 mile south of county route J, in the early afternoon. The temperature was approximately 80-85 degrees F.

A short time after the incident, I wanted to test the emergency brake, so I set the emergency, started the car, placed it in Drive, and pushed the accelerator to the floor. All seemed normal.

The Prius was towed to Rosemurgy Toyota in Wausau, Wi.

To date, service is not complete.

However, this is Toyota's explanation:

The Toyota rubber floor mat was against/over/on the accelerator, causing it to be pushed down (here, I was shown a picture which purports to show this).

But, note what I did when I got into the car: I set the brake, pushed the Power Button (engine did not suddenly rev) and I shifted into Drive (could I do that with a reving engine)? Lastly, I pushed down on the accelerator peddle!

There was at least one other incident reported on an '05. Toyota states that what occured on Monday, June 25, 2007 to my '06 Prius had never happened before.