Reading a spark plug is a great way to check your engine's health. Mechanics often read spark plugs to diagnose fuel mixture, ignition, and engine condition. Here's a clear guide for changed spark plugs increased vibration StromTrooper Why Is Your Engine Shaking? It Could Be a Faulty Ignition Coil! If your engine is vibrating unusually, losing power, or showing a Check Engine light, a bad ignition 9 Causes Of Engine Vibrations (And What To Do About It)