We may receive a commission on purchases made from links. When it comes to engine care 101, a spark plug replacement — also referred to as a tune-up — is an essential task. Spark plugs, as the name ...

If you've ever seen a mechanic draw a tiny line on a spark plug before changing it, they're not performing witchcraft — they're indexing it. The idea is simple. Most standard types of spark plugs have ...

We earn commissions from purchases you make using links in our articles. Learn more. You don't have to pay a mechanic to change your spark plugs. Giving your engine fresh spark plugs should be part of ...