What are the causes of car engine idle vibration?
3 Answers
Car engine idle vibration is caused by: 1. Dirty throttle valve; 2. Spark plug failure; 3. Engine cylinder misfire; 4. Aging rubber components inside engine mounts and transmission mounts. The car engine is the device that provides power to the vehicle, determining its power performance, fuel economy, stability, and environmental friendliness. Car engines are classified into diesel engines, gasoline engines, electric vehicle motors, and hybrid motors. Both gasoline and diesel engines belong to reciprocating piston internal combustion engines, converting the chemical energy of fuel into mechanical energy of piston motion to output power.
I often notice severe engine shaking at idle, which usually has several causes. The most common is ignition system failure, such as worn spark plugs or faulty ignition coils, leading to uneven combustion in each cylinder and affecting engine stability. Secondly, fuel system issues like clogged fuel injectors prevent proper fuel delivery into the cylinders, reducing combustion efficiency. Additionally, air system problems are frequent, such as excessive carbon buildup in the throttle body restricting air intake or small leaks in the intake manifold. Mechanically, worn engine mounts can make the entire engine shake more noticeably. If not repaired promptly, the shaking will worsen, making driving both uncomfortable and dangerous. I highly recommend regular major maintenance checks on these points to avoid unnecessary trouble.
When I first bought my car, I often encountered idle shaking, and later realized there are quite a few reasons for it. Generally, spark plug erosion is the main cause—over time, filament breakage can lead to intermittent ignition. Fuel issues are also critical; impure fuel or clogged fuel injectors can cause unstable combustion of the air-fuel mixture. Additionally, excessive carbon buildup in the throttle body can obstruct airflow. I also noticed that small components like aging or loose engine mounts can amplify the shaking sensation. If not addressed promptly, fuel consumption can spike, and long-term damage to the car may occur. So I’ve learned my lesson—I clean carbon deposits and check spark plugs every six months, spending a little now to save on major repairs later.
