What are the causes of engine vibration at idle speed?
4 Answers
Engine vibration at idle speed can be caused by: 1. Carbon deposits in the throttle body, requiring cleaning; 2. Damage or hardening due to aging of the engine mounts; 3. Faulty spark plugs in the ignition system leading to poor ignition performance; 4. Poor fuel quality; 5. Carbon deposits and aging in the engine; 6. Issues with the engine mounts; 7. Abnormal fuel pump pressure; 8. Incorrect readings from the intake pressure sensor. The troubleshooting methods for engine vibration at idle speed include: 1. Inspecting the idle speed control motor by turning the ignition switch to position 1—if no sound is heard, repair or replace the idle speed control motor, ECU, and related circuits; 2. Checking the throttle position sensor; 3. Inspecting the fuel injectors and crankshaft position sensor.
I remember driving that old car ten years ago, the engine shook violently at idle, as if it was about to fall apart. The main reasons were old spark plugs failing to ignite properly, or faulty ignition coils causing uneven ignition. Additionally, clogged fuel injectors couldn't spray enough fuel, or issues with the air system like intake manifold leaks, which disrupted the air-fuel mixture ratio and caused abnormal combustion. Worn-out engine mount rubbers shouldn't be overlooked either, as they destabilize the entire engine block. Carbon buildup on valves or pistons can also hinder the combustion process. Once, my car was shaking badly, and replacing the spark plugs made a huge difference. Regular maintenance and checking these components can prevent shaking and unstable idling, which affects driving comfort and even safety.
I enjoy tinkering with my car, and engine idle vibration is usually something I can fix myself. First, check the spark plugs; if they're blackened or worn out, replace them. Faulty ignition coils often cause misfires leading to vibration. For fuel-related issues, if the fuel injectors are dirty, flush them with a cleaner. Leaks in the air intake system due to loose seals need to be checked at the connections. Engine mount damage makes vibrations more noticeable. When there's heavy carbon buildup, adding a cleaner and driving at high speeds can help. Sensors, like the crankshaft position sensor, are also common culprits. These self-checks can save on repair costs and prevent vibrations from worsening and affecting driving.
With years of research on cars, idle shaking is usually caused by ignition system failures, such as faulty spark plugs or coils leading to misfires. Insufficient fuel supply, like clogged injectors or unstable pressure, can also be a factor. Air leaks in the intake manifold result in an imbalance of the air-fuel mixture. Mechanical issues, such as aging engine mounts losing their cushioning effect, contribute as well. Carbon buildup affects valve operation, leading to incomplete combustion. Prompt inspection of these components can resolve the issue.
