How to Change Your Spark Plugs Like a Pro 🔧🚗 Spark plugs are small but powerful – they help your car start, save fuel, and perform at its best. Most OEM plugs last 30k–60k miles, but once they’re old, your engine will tell you: rough idle, poor acceleration, bad fuel economy. All you need is the right plugs for your engine (4/6/8 cylinders), a spark plug socket, basic tools, and patience. Disconnect the battery, pull the ignition coils, remove the old plugs, hand-thread the new ones, tighten t