2. Vacuum Leak: A vacuum leak can cause a lean fuel mixture, leading to rough idling and engine shaking. Inspect all vacuum hoses for cracks or disconnections and replace or repair them as needed.
3. Fuel System Issue: Check for any issues with the fuel system, including clogged fuel injectors, a malfunctioning fuel pressure regulator, or a failing fuel pump. These can cause the engine to run rough and fail to stop when the ignition is turned off.
4. Ignition System Problem: A faulty ignition switch, a worn-out distributor cap or rotor, or damaged spark plug wires can cause ignition issues, leading to rough running and engine shaking.
5. Malfunctioning Idle Air Control Valve: The idle air control valve (IAC) regulates the amount of air that bypasses the throttle plate when the engine is idling. A faulty IAC can cause the engine to run rough and idle erratically.
6. Camshaft Position Sensor: A malfunctioning camshaft position sensor can disrupt engine timing, resulting in rough running and shaking. Check the sensor's functionality and replace it if defective.
7. Faulty Throttle Position Sensor: A faulty throttle position sensor can send incorrect signals to the engine's computer, leading to engine shaking and rough idling. Test the sensor and replace it if necessary.
8. Engine Mounts: Worn or damaged engine mounts can cause excessive vibration and shaking. Inspect the mounts for signs of wear and tear, and replace them if necessary.
9. Check Battery: A weak battery may not provide enough power to fully turn off the ignition system. Ensure the battery is in good condition and has enough charge to power the ignition switch.
If the issue persists after inspecting and addressing these potential causes, it is recommended to seek assistance from a qualified mechanic for further diagnosis and repair.
