The function and purpose of the car distributors are quite direct. It takes the spark that is generated by your car's ignition coil and distributes it out to the personal ignition wires at the appropriate time to create combustion inside the combustion chamber of every cylinder. Almost all car distributors use a distributor cap, and either a rotor or a set breaker points and condenser to improve the distribution of spark energy. As the rotor in the matter of most modern cars swings across it's circular arc, the tip of it makes electrical connection with the distributor cap to send the electrical current to the ignition wire and later the spark plug.
A points system works in much the same way, but a points car distributor system has some very important disadvantages and therefore forth are not used in modern cars, and still in cars that have been built over the past 30 years. Any problems with contact or oxidation on either of the rotor or distributor will cause random misfire issues and are generally the main cause of random misfires. At times random misfires can be caused by other issues for example a bad distributor control module or cracked coil, but 9 out of 10 times, it's generally just the cap or the rotor.
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