A spark plug thread chaser isn't always the answer, but it can make a big difference when you're installing fresh new plugs.

We may receive a commission on purchases made from links. A spark plug isn't just one standard item, and the market is full of different types, materials, and designs. They're each made to run best ...

For hot rodders, spark plugs are often nothing more than inspection tools that reveal whether an engine is running too rich, too lean, or just right. Street guys look for a nice tannish-brown tint on ...