ORIGINAL: CmordaBest
when you said a "runaway" what did you actually mean. was it just happen sometimes or is it when the throttle gets "stuck open" when batteries go dead or something. if this is the case, then a fail safe which can be picked up for about £10-£30. they automatically put the throttle to idel when a signal is lost or batteries run out.
hope this helped[:-]
Incorrect my friend ! A failsafe only guards against loss of signal, NOT loss of power !

Ive used a failsafe since the day I bought the car.