if you have changed the radio and receiver and it is still doing it i think it is still going to be a bad speed control. Sounds as if the speed control is seeing a signal from the reciever all the time. it is possible that you had two bad radio's or recievers but not very likely. have you tried shooting an email to novak and ask thier advice? one more thing you might try. switch the leads. use the leads from the reciever that would normally go to your steering servo and us them as throttle. in a sense you would be steering with your trigger and gassing with your wheel. plug it in to the speed control and try the set up again. understand?