The phrase"tune-up" in fact is applicable only to older vehicles with out electronic ignition (prior to 1981). With these automobiles a tune-up might generally be expected every 15,000 - 20,000 miles and was comprised of changing the spark plugs, ignition contact points, rotor as well as distributor cap and modifying the ignition timing along with the carburetor On modern day automobiles designed with electronic ignition, fuel injection and computer controls, the phrase "engine performance maintenance" is really a better term. A "tune-up" of these more recent automobiles is definitely an orderly procedure for inspection, computer diagnosis, tests and adjustment to keep up peak engine performance, optimum operating efficiency and low exhaust emissions. In this process, spark plugs, plug wires, sensors, and modules could possibly be swapped out. The regularity of which a more modern automobile requires a tune-up would depend more upon driving conditions than mileage and suggested tune-up frequencies vary between 30,000 - 100,000 miles, with respect to the maker. To understand how frequently your automobile requires a tune-up, look at your owner's manual or talk to your neighborhood automobile service agency.