Why does a car idle shake like a twitch?
3 Answers
Reasons why a car idles and shakes like a twitch: 1. The vehicle's ignition system has malfunctioned; 2. Components in the ignition system have become loose; 3. Severe carbon buildup in the engine; 4. Aging of engine components; 5. Excessive carbon buildup in the throttle; 6. The air filter has not been replaced in time; 7. Too much carbon buildup in the fuel injector; 8. Problems with the ignition system; 9. Unstable oil pressure. Idling in a car is not a speed but rather a working condition. When the engine runs without load, it is called idling. When the engine is running, if the accelerator pedal is completely released, the engine is in an idling state. The engine speed during idling is called the idle speed, which can be adjusted by modifying the throttle opening size, among other methods.
My car sometimes idles roughly, shaking like it's shivering. This is usually caused by unstable engine operation. Worn spark plugs or faulty ignition coils can lead to uneven ignition - when one cylinder misfires, it's like walking unsteadily with a missing leg. Carbon buildup in the throttle body blocks airflow, causing idle speed to fluctuate. A malfunctioning mass airflow sensor provides inaccurate readings, disrupting the air-fuel mixture ratio. When engine mount rubber components age and lose their damping ability, you'll feel vibrations when braking. Fuel system issues like clogged injectors causing insufficient fuel supply also create fluctuations. You should systematically diagnose the problem - start by checking the ignition system (spark plugs and high-voltage wires). If the issue persists, read OBD trouble codes to identify the root cause, then address it specifically. Don't ignore the problem to avoid causing more serious engine damage.
As someone who has driven for over a decade, I've encountered plenty of idle vibration issues where the entire cabin feels like it's bouncing. The most common cause is worn-out spark plugs - replacing them is cheap and effective. Clogged fuel injectors from carbon buildup can cause unstable fuel supply, which cleaning can resolve (using low-quality fuel worsens this). Worn or cracked engine mounts make driving feel like sitting on a massage chair - replace the rubber bushings promptly. Listen for symptoms: if you hear sputtering sounds or excessive vibration, it might indicate a misfiring cylinder. Immediately stop the car, turn off the AC to reduce load, and briefly check spark plug gaps, but don't delay proper repairs. Always consult a reliable mechanic for diagnosis - prioritizing safety saves money, ensures peace of mind, and delivers smoother rides.
