We have all had this happen at our car club in Thailand. We found out that there are two reasons for this. 1 is that the plug socket from your battery to the receiver is loose or dirty. Try cleaning the plug sockets and if that doesn't work change both the male and female sockets. 2 is to make sure you have a protective rubber cover over your receiver. Fuel and dirt can get into your receiver to servo sockets very easily if the receiver is not covered. We have all had this problem in the past but not any more. All our receivers are covered and we clean our battey to receiver plug sockets often.