PART One: What is a Tune-Up?
The Ignition systems works together with the fuel management system to provide a vehicle operating properly. What is generally considered the tune-up today is just the replacement of the spark plugs. The tune-up is listed in the Recommended Maintenance list as a preventive maintenance procedure at a specified mileage. Some vehicles have what is called “coil over plug” ignition systems. That means there is an ignition coil over each spark plug and no spark plug wires. This tune-up amounts to replacing the plugs and inspecting each coil and coil insulation boot. I can’t recall ever recommending that all the coils be replaced at once as that would be very costly. The next type of ignition system (mostly on older vehicles) has a distributor, coil, spark plug wires and plugs. This type of ignition system tune up normally replaces the distributor cap and rotor, wires, and plugs. As the engine installations became more complicated this type of ignition system was replaced as they were expensive and difficult to maintain.