People who have the right tools can tune up their engines for free, although full tune-ups sometimes require replacing spark plugs and other components. However, many of the steps typical tune-ups entail aren't possible on newer cars.
Traditional tune-ups deal with checking the vehicle's spark plugs and adjusting the timing of various engine components in addition to inspecting parts. Newer engines typically adjust their timing automatically, and many use computer controls, making them impossible to tweak. However, drivers can still clean parts of the engine and look for signs of premature damage. Repairing or replacing a faulty component before it fails completely can allow drivers to avoid more expensive repairs in the future.