The part of the motor vehicle electric system which distributes the "spark" to the various combustion cylinders is the

the rotor and distributor assembly system. For the engine to run smoothly, the cylinders must fire in a particular order. The rotor and distributor accomplish this by sending the "spark" to the cylinders at closely timed intervals. Should the rotor and distributor assembly fail to do this correctly, the engine combustion would be very rough and cause backfiring and other problems.