I'm guessing your running a nitro, so a servo for throttle and one for steering. Have you checked the reciever battery, make sure it's charged or fresh batteries put in and there are no exposed wires to the reciever. Also put some rubber bands between the end of the slide where the throttle servo connects and then around the carb body tight enough to return it to idle if you lose power from the battery (have experience from a run away) because failsafes don't work if the reciever battery is dead. It sounds like your losing power to the reciever but also put fresh batteries into your transmitter as well to cover your bases. If you have tried the fresh or charged batteries then you have to move onto transmitter or reciever problems but you don't mention anything about the batteries so try it you may be surprised. Hope this helps.