What Causes Intermittent Shaking at Idle?
2 Answers
The causes of intermittent shaking at idle are: 1. Severe engine carbon buildup; 2. Ignition system issues; 3. Unstable fuel pressure; 4. Aging engine components. Common causes of vehicle shaking include excessively dirty throttle bodies or excessive carbon deposits in fuel injectors. Check the working condition of spark plugs, high-voltage wires, and ignition coils. Poor ignition system performance or faulty spark plug firing can also lead to such symptoms. If the vehicle still shakes at idle, it is recommended to visit a 4S shop to check fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings/malfunctioning of the intake pressure sensor can both cause body vibration.
As an experienced car owner, when I encounter intermittent shaking at idle, I suspect the main causes are excessive carbon buildup inside the engine or unstable ignition system. Frequent low-speed driving in urban areas tends to accumulate carbon deposits near the cylinders or throttle body, causing unstable idle RPM. I would first check the spark plugs to see if the electrodes are worn or the gap has widened. Replacing faulty spark plugs often solves the problem. Fuel system issues like clogged injectors or insufficient fuel pump pressure can also cause uneven fuel delivery leading to shaking. Electronic components such as dirty idle control valves or faulty sensors misreading data may also be culprits. If left unaddressed, the shaking can accelerate engine component wear and even increase fuel consumption. For safety, it's best to visit a repair shop promptly for comprehensive diagnostics—their professional tools can quickly pinpoint the issue.
