Incorrect Spark Plugs: If the newly installed spark plugs are not the correct ones for your vehicle or if they have an incorrect gap, it can cause misfires and lead to a shaky engine. Ensure the spark plugs' type, size, and gap match the manufacturer's specifications.
Loose Spark Plug Wires: Make sure the spark plug wires are properly connected and securely attached to the spark plugs and the distributor (if applicable). Loose connections can cause misfires and result in a shaking engine.
Damaged Spark Plug Wires: Check the spark plug wires for damage, cracks, or tears. Damaged wires can lead to spark leakage and misfires, which can cause the engine to shake. Replace any damaged spark plug wires as necessary.
Vacuum Leak: If there is a vacuum leak in the engine, it can cause a lean fuel mixture and result in a rough idle and engine shaking. Inspect the vacuum lines for cracks or disconnections and ensure they are properly connected.
Faulty Ignition System Components: Issues with other components in the ignition system, such as the ignition coil, distributor (if applicable), or ignition control module, can also lead to engine shaking. If the problem persists after checking the spark plugs, wires, and vacuum lines, it is recommended to have the entire ignition system inspected by a qualified mechanic.
