2143 servo on the throttle is overkill ! You have too much money !

If the throttle linkage is not set correctly, you can burn them out very easily. Perhaps your throttle servo is very near the engine which causes unwanted vibration... Do you mount rubber gromets unber the servo ears when you install them on the car? What car is this? These rubber gromets can isolate most of the unwanted vibration which can kill the servo easily.