An automotive tune-up is an orderly process of inspection, diagnosis, testing, and adjustment that may be needed to maintain peak engine performance or restore the engine to original operating efficiency.
Tests by the Champion Spark Plug Company showed that an average 11.36;pc improvement in gas economy could be expected after a tune-up. A change to new spark plugs alone provided a 3.44;pc decrease in fuel use. As for emissions, significantly lower emissions were recorded at idle after a complete tune-up on a car needing service. An average 45.37;pc reduction of CO emissions was recorded at idle after a complete tune-up, HC emissions were cut 55.5;pc.
The tune-up is also a good opportunity to perform a general preventive maintenance check-out on everything in the engine compartment. Look for failed or about to fail components such as loose or damaged wiring, leaking fuel lines, cracked coolant hoses, and frayed fan belts.
Chrysler recommends replacing spark plugs at 30,000 mile intervals on cars equipped with catalytic converters and 15,000 mile intervals on non-converter cars. It would be a good idea to check the spark plugs and ignition system before those mileage readings as a preventive maintenance measure. If you are experiencing starting problems or below average fuel economy you will, of course, want to tune the car before those intervals. Each step of the tune-up should be followed in the order given. If any of the specifications on the emission control sticker under your hood differ from those given in the "Tune-Up Specifications" chart, use the figures from the sticker. Running changes made by the manufacturer are often incorporated into the sticker. When you decide on a tune-up schedule for your car, follow it religiously. A regular tune-up will head off winter no-starts and summer stalling. A small investment in time and parts pays off in improved gas mileage and engine performance.