A tune-up can also be a crucial form of preventative maintenance that helps you get the jump on catastrophes and keep costly repairs at bay, and it might even help you sort out problems that the onboard diagnostics system isn’t equipped to detect. If you aren’t working with an OBD system, you definitely need to be performing a tune-up religiously, as it will tell you a lot about your engine’s current running condition.
So, what the heck is an engine tune-up exactly? In truth, it’s one of those things that can mean different things in different situations. We’re here to talk about exactly what a tune-up is and what you’ll want to know before you dive in.
If the engine is in relatively good condition, a tune-up really only consists of a few basic steps. First, you’ll want to inspect the fluid levels, their condition, and perform an oil change if necessary. You’ll also want to inspect the serpentine belt and hoses for any signs of age (i.e., cracking or damage) and replace them if necessary—something you can expect to do on a neglected engine. Of course, a fresh set of spark plugs and a thorough inspection of the ignition system are in order, along with cleaning the major fuel and air delivery components.
In the case that an engine has known issues that are causing rough running conditions, you’ll want to jump on them first. Something like a misfire can be linked to a bad plug that you’re replacing anyway, but you’ll want to make sure a faulty coil or plug wire isn’t left in place as it can let your efforts go in vain. The same thing applies to any fluid, vacuum, head gasket, or manifold leaks that can be causing you heartache.
Source : https://www.popsci.com/cars/car-engine-tune-up/
