Spark plugs. The Best Spark Plugs in the World and Why, DIY and car repair with Scotty Kilmer. How spark plugs work. Copper spark plugs vs platinum spark plugs vs iridium spark plugs, which is better What are the best spark plugs to buy Best spark plugs for performance and horsepower. Spark plugs replacement. Buying spark plugs. Why spark plugs fail. Car advice. DIY car repair with Scotty Kilmer, an auto mechanic for the last 51 years.