We experienced a jammed open throttle years ago in a minivan. The cruise control was aftermarket, and it used a chain at the throttle end of the pull cable. If you accelerated to pass while the cruise was engaged, the chain would droop from line slack and sometimes snag. we experienced it several times, and simply drove by key on / key off / on / off down the road until we could pull over and (figure out what was happening) later (fix it). Good times. Helped that it was a manual. Dad was driving the first time. There was no panicking, though nobody liked it.