reading your spark plugs

Your spark plugs are like a cipher. And to read a cipher code, you usually need a cipher key. That’s what this is—a cipher key that is going to help you “read” your spark plugs and understand what they’re telling you about how your engine is running. Is your engine running too rich? Too lean?

Listen closely because your spark plugs may be trying to tell you something. Is your engine running too lean? Too rich? Is there an issue with oil control or ignition timing? Or is everything just fine with your engine? Like the mechanical version of the Magic 8-Ball, your spark plugs may have the answers for you. The trick is