The word "tune-up" actually applies only to older cars, on which you can perform the traditional work associated with the term, which typically includes spark plug replacement, ignition contact point replacement, dwell adjustment, ignition timing adjustment and carburetor idle and mixture adjustment.
The majority of vehicles would need an "engine performance maintenance," for they are equipped with an electronic ignition (no points) and most likely more than one on-board computer which automatically adjusts items like the ignition timing, fuel mixture and idle speed.
An automotive tune-up is an orderly process of inspection, diagnosis, testing, and adjustment that is periodically necessary to maintain peak engine performance or restore the engine to original operating efficiency.
The tune-up is also a good opportunity to perform a general preventive maintenance check on everything in the engine compartment and look for failed or about to fail components such as loose or damaged wiring, leaking fuel lines, cracked coolant hoses, and frayed belts.
Spark plug life and efficiency depend upon the condition of the engine and the combustion chamber temperatures to which the plug is exposed. These temperatures are affected by many factors, such as compression ratio of the engine, air/fuel mixtures, exhaust emission equipment, and the type of driving you do.
Engine control computers precisely time when fuel is injected into the engine and when spark plugs fire. The engine computer tells the coil when to release the power to the spark plug. The electricity travels through a wire from the coil to the spark plug. At the tip of the plug, a spark jumps between two electrodes and ignites the gas in the combustion chamber. Some engines have more than one coil and can wear out needing occasional replacement.
Spark Plug replacement intervals range from 30k to 100k miles, check in your Owner's Manual for your specific vehicle. We recommend replacing your spark plug wires, or coil boots, when replacing spark plugs.