Tuning up a vehicle is not like it used to be. You used to have to tune-up an engine every 30,000 miles.

Today, tune-ups are recommended usually at around the 100,000-mile mark. And the only major replacement components are the spark plugs, because with electronic ignition, there are no points to replace; and timing is set, so you don't have to use a timing light to time the engine as in the past.

Although it is easier in some respects to tune-up an engine today, there are also additional considerations. Because of transversely mounted engines and modified engine designs, it is sometimes difficult to access the spark plugs to remove them. So even though you are spending less money on parts (spark plugs only, versus points, rotor, and plugs), you end up spending more money on labor in order to take apart and reassemble part of the engine to access the plugs.

If you are going to attempt the job yourself, first and foremost, make sure the ignition is off. (Caution: changing spark plugs and tuning up your car with the ignition in the "on" position can result in severe electrical shock or even death.) You will need whatever tools necessary to disassemble parts of the engine. This includes a socket wrench, sockets (inch and/or metric), a spark-plug socket, an extension, and a screwdriver. But you may need specialty tools that allow you to remove turn special bolts and screws. These are available through auto parts stores. You will most likely need a torque wrench, also, to torque down the spark plugs to specifications. Lastly, you will need a repair manual for your vehicle, anti-seize compound, the proper replacement spark plugs and a spark plug gap-measuring device. (Even though all spark plugs today are pre-gapped, it is best to measure the gap with this device, available at any auto parts store for a couple of dollars, just to make sure the gap is correct.)

Once you have disassembled the engine to gain access to the plugs, use your socket wrench to carefully unfasten them from their mountings, then discard them. Measure the spark plug gap on the first plug to make sure it is correct according to your manual. Apply some anti-seize compound to the threads. Use your socket wrench, extension and spark plug socket to carefully install the new plug into its hole in the cylinder head. Be very careful not to over-tighten the plug; you could strip the threads from the cylinder head, which would result in a costly repair. Using the torque wrench, torque down the spark plug as tightly as recommended in your repair manual. Now install the rest of the plugs in the same way, measuring each gap, using anti-seize compound, and torqueing down each one to specifications. After you have installed your new plugs, reassemble the engine components your removed and you are finished.

It is hard to imagine that as far as tune-ups are concerned you are good to go for another 100,000 miles. But with modern fuel injection and electronic ignition, there is very little that needs attention.