2001 SS, very cold weather, kicked forward and car turned off while driving.
 

This morning the weather was cold (-20c or so) I didn't have it plugged in overnight, however started up no problem. Let it warm up for 15-20 minutes. Went for a drive. At some point it sorted kicked forward/accelerated on it's own then turned off. Did this about twice. Started up each time and then drove for another 30 minutes and had no problems after that.

The transmission is relatively new. Could use an oil change. No CELs on. The car just turned right off completely while driving on the road (after kicking forward like that), steering wheel went hard and had to come to a complete stop, restart it and go again.

Any ideas? Just the cold weather? Maybe had to get the juices flowing? I've had it over 3 winters here which get to -20 and -30 and never had the problem before.