Spark Plugs A spark plug is a major key component in the running of your engine and its capability. A faulty spark plug can deplete your engines peak performance. Replacing them as soon as they start to give you trouble is key, if not addressed, one faulty plug can cause more problems for your vehicle down the road. At the same time, not supplying your ride with the optimum performance that it can live up to. Not all are the same, there are various things to take into account when replacing a spark plug, and most importantly is your vehicle make and model. Take a browse through our big selection to find the one you need to get your vehicle running and operating to its full potential. Keeping in mind that a spark plug, though small in size, plays one of the biggest parts in your engines reliability and performance.