As the vintage picture on the left shows "Tune-Up" has been with the automotive industry for some time! However, some things never change, such as the need for periodic preventive maintenance. But a tune-up is one job that's changed a great deal over the course of automotive history. The outdated term is still widely used by many people to describe a service procedure that's supposed to make an engine run better.
There's no absolute definition of what exactly a tune-up should include, but most would agree that it involves replacing the spark plugs and performing other adjustments to maintain or restore like-new engine performance. The problem is there's not much that can adjusted under the hood on many late model vehicles. Ignition timing is fixed and controlled by the engine computer, as is idle speed and the fuel mixture. You can still check base timing (maybe), idle speed and various emission functions to make sure everything is functioning within factory specs and are functioning properly. But there really isn't much of anything left to "tune." Yet motorists still want tune-ups and believe tune-ups are an important and necessary service.
A simple maintenance type tune-up (a new set of plugs) may make an engine easier to start, improve fuel economy, lower emissions, restore lost pep and power, and so on provided engine performance deteriorated because of worn or fouled spark plugs. But if the problem lies elsewhere, a new set of plugs alone won't do the trick and A "tune-up" under these circumstances would be a waste of time and money.
The first thing you should do, therefore, when someone asks about a tune-up is to find out why he thinks he wants one. If he gives any reason other than scheduled maintenance, he has a performance problem that will require additional testing to identify the cause (or causes) of the problem. Only after the performance problem has been diagnosed should any parts be replaced.
The word 'Tune-Up' has a little different meaning today, but one thing is for sure, no vehicle that's yet been built can even come close to going 100,000 miles without needing some type of maintenance or repair.
