The term tune-up started with the Ford Model T, the spark coils were known as tremor coils. They made a sound when firing, that created a certain pitch. Many technicians back then used a tuning fork to mimic the sound produced by a properly adjusted coil. When the coil was adjusted to match the sound of the tuning fork the tech would know it was adjusted for peak performance. Today’s vehicles the term tune-up is outdated and is now classified as scheduled maintenance items.