Sometimes customers ask for a tune up thinking it’s the answer to an engine running problems. Although a lot of engine running conditions are cured by a tune up, it is not a guarantee "fix all". It is however, a great place to start as your tune up related parts are exposed to wear and contaminating conditions, therefore, they must be in good working order before looking for additional problems. In the old days, a tune up used to be done at least once a year because the points wear out and the timing would automatically require adjustment after they were replaced. Spark plugs and filters were replaced at the same time which everyone called a "tune up". Nowadays, everything is computer controlled and new breeds of maintenance habits are required and a so-called "tune up" is a service based on mileage.
Following your owner’s manual is an excellent guide of when maintenance is required. Regular spark plugs are good for around 30,000 km’s and some platinum plugs are available with an expectant life of 100,000 km’s or more. Points and condenser are a thing of the past as a matter of fact the distributor is on its way out too. With that said, the distributor cap and rotor is a dying breed. However, all filters should be regularly changed, including the PCV valve at approximately 30,000 km’s or sooner under extreme conditions. Plug wires should also be closely looked at for arcing, rubbing and chaffing from the high under hood temperatures and because of the close proximity of other components. Other parts that are "tune up" related is servicing/replacing the oxygen (02) sensor. Again it’s a service based on mileage. The purpose of the O2 sensor is that it measures the oxygen content in the exhaust. It then sends a signal to the computer, which responds accordingly to achieve the cleanest emissions and best fuel economy. The cost of a modern "tune up" has gone up as well. Tune up parts for a modern fuel injected vehicle such as an O2 sensor on average cost about $150 (2009 pricing) but can cost as high as $500 depending on the vehicle, iridium spark plugs at $25 each per cylinder or our preferred NGK V-Power spark plugs at approx. $5 each and a fuel filter can reach on average $50 or more. So, it’s impossible to quote a firm price on a proper job because it depends on what your vehicle needs. However, I do know that if someone offers a so called "tune up" for $100 or less including parts, it’s wise to ask yourself what kind of job you are getting and best to drive the other way.