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 ...

So, it's time for new spark plugs. Your hands are covered in grease, you're twisting the ratchet, and –- snap. Half the spark plug stays lodged inside your cylinder head like a nonpaying tenant who ...