I don't know if this is related but you may want to check it out. I had installed a brand new Sphere(TC) and novak 10.5 motor. In the motor I had too long motor screws and within a 30 seconds the motor had fried. I took that car back to the pits and put a borrowed motor in the car(again with the too long screws) and it was glitching. I took the motor screws out and the glitching went away. Thats how I found out that the motor screws were too long. Does your motor/speed control glitch even when the youhold the motor in your hand?