Yesterday, I was driving on the highway at a 65-70 miles per hour (basically pushing it for my '96 RAV4). Suddenly, the car turned off. The engine cut out and the battery and oil signal came on.
It did not lurch as if I had popped the clutch, nevertheless, I went to restart it as I was going down the hill and it made it home for the next 40 miles.
You may have a faulty ignition switch. Do you carry many keys on your key ring? This will wear out an ignition switch and cause it to cut out intermittently.
Also check with Toyota to see if they have a Tech Service Bulletin (TSB) for this problem. Some cars have had recalls for defective ignition switches.