Go to the usual suspects....Make sure everything is right mechanically. Make sure you have the right coils. Ohm them out to make sure the right coil is good and not burned. Make sure the kickout levers and pivot points are operating freely. Make sure the plunger moves freely in the sleeve. Good coil stop. Make sure the switch contacts are clean and mate squarely. I usually set up the switch blades to engage at the bottom of the range to let the ball settle in before the contacts mate.