Under the Hood: Spark Plug and Ignition Wire Replacement Melted Spark Plug Mechanical Malarkey Worn spark plugs can cause poor performance, misfiring, and higher fuel consumption. Replace them when you notice rough idling, slow pickup, or engine vibration. Thank you for choosing #ELZBrunei . Visit your Why Your Car is Vibrating When Idle How to Fix It Spark Plug Terminal Design Assures Reliable Connection ETCO Causes of Car Engine Vibration While Driving and Stopping* Engine vibration can be a frustrating issue for car owners. Understanding the underlying causes is crucial for proper diagnosis and repair. *Primary Causes