In order to extract the full measure of performance and economy from you car's engine it is essential that it be properly tuned at regular intervals. Although the tune-up intervals for the newer models have been stretched to limits which would have been thought impossible a few years ago, periodic maintenance is still required. A regularly scheduled tune-up will keep your car's engine running smoothly and will prevent the annoying minor breakdowns and poor performance associated with an untuned engine.
A complete tune-up should be performed at the interval specified in the Maintenance Intervals chart in Section 1. This interval should be halved if the car is operated under severe conditions, such as trailer towing, prolonged idling, continual stop and start driving, or if starting and running problems are noticed. It is assumed that the routine maintenance described in the first section has been kept up, as this will have a decided effect on the results of a tune-up. All of the applicable steps should be followed in order, as the result is a cumulative one.
If the specifications on the tune-up label in the engine compartment disagree with the Tune-Up Specifications chart in this section, the figures on the sticker must be used. The label often reflects changes made during the production run.