I have 2 Quantum speed controls one stutters under hard acceleration (just out of a corner) and the other just doesn't have the zip it had last year. The car doesn't have the speed it had last spring. The batteries are new and test fine the motors have been equal to what was in the car last year. Could an ESC still operate but have power loss? It acts like a V-8 with 2 cylinders missing. I have both set for max punch and they have been reset several times to make sure it was getting the proper trigger throw. Nothing else has changed.