Years ago, the purpose of doing a tune-up was to make the engine run better. The process used to involve replacing the spark plugs, spark plug wires, gapping the points, and possibly installing a new condenser, distributor cap, and rotor. At the same time, the air filter and fuel filter would be replaced as part of the process. The mechanic would adjust the points, set the timing and the fine-tune the carburator's fuel-air mix. The general belief was that some of these components would already be visibly worn out and the others would be likely fail in the relatively near future, so it just made sense replace them all at the same time. The mechanic would hook a timing-light and check the ignition system. Tune-ups were usually done once or twice each year (depending on the milage driven) and cost was about $100 and the car would run smoothly when finished.
Modern cars are completely different. They no longer have carburators and come with electronic ignition systems and multiple on-board computers. Today's sophisticated engine management systems require training and tools that didn't even exist 20 years ago. The sensors, actuators, electronic modules and fuel injectors are all controlled by the engine management system.
If a car engine is running rough, a technician taps into the vehicle's data-port and transfers the engine's data into a scanner. That data is then analyzed and interpreted to determine what's wrong. This diagnostic process tells the mechanic what parts are malfunctioning, but still there is no machine made that will determine why a particular component is "out-of-spec". That's where the mechanic's skills and experience are important. Similarly, there is no machine made that can tell a doctor which specific medicine to prescribe. An engine problem could be caused by one of two or even three actuators or controls that are malfunctioning and causing another component to behave erratically. That unit may be perfectly fine and not need replacing at all, so the mechanic depends his skills and years of experience to pinpoint the actual root of the problem. On modern-era cars, it is almost always cheaper to spot and repair an engine problem by doing a diagnostic process and replacing only the part that is actually in failure-mode, than to replace a pre-set shopping list of parts all at the same time. No one wnats to pay for a repair that does not fix the problem, so we recommend a diagnosis when your car isn't running right.
Of course, we still do traditional tune-ups on older vehicles, but if you've got a newer model car, we know how to fix that too!
Golden State Transmission and Muffler 10792 Olson Dr., Rancho Cordova, California 95670 916.853.1788