In order to extract the full measure of performance and economy from your engine, it is essential that it be properly tuned at regular intervals. A regular 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 properly tuned engine is also important to the control of tailpipe emissions.
The adjustments associated with engine tune-up should be checked every year or 12,000 miles (19,300km), whichever comes first, or more often if the vehicle is operated under severe conditions, such as trailer towing, prolonged idling, continual stop and start driving, or if starting or running problems are noticed. Refer to the Maintenance Intervals Chart in for specific component replacement intervals. It is assumed that the routine maintenance described in has been kept up, as this will have decided effect on the result of a tune-up. All of the applicable steps of a tune-up should be followed in order, as the result is a cumulative one.
If the specifications on the emission information label in the engine compartment disagree with the Tune-Up Specification chart in this Section, use the figures on the label. The label often includes changes made during the model year.