What are the reasons for car shaking at idle speed?
3 Answers
The reasons for car shaking at idle speed are: 1. The throttle is too dirty or the fuel injector has excessive carbon deposits; 2. Poor performance of the ignition system or bad spark plug firing condition; 3. Unstable oil pressure: If the fuel pump supply pressure is abnormal or the intake pressure sensor value is incorrect and working poorly, it will cause the car body to shake; 4. Aging of engine components: Car shaking is also related to the aging of engine mounts. Engine mounts are actually the shock absorption system of the engine, responsible for absorbing the slight vibrations during engine operation. If there is a problem with the engine mounts, these vibrations will be transmitted to the steering wheel and the interior of the car, causing shaking at idle speed.
I've been driving for over a decade, and common idle shaking is mostly due to aging spark plugs or ignition coils, especially in older cars. Last time my car was shaking badly, and after inspection, it turned out the engine mount rubber pad was loose—replacing it fixed the problem. Also, too much carbon buildup in the throttle body can cause shaking; cleaning it regularly helps. If the fuel system isn't running smoothly or the fuel injectors are clogged, shaking can occur too. Another issue could be insufficient or degraded engine oil, leading to poor lubrication and unstable engine performance. In short, minor shaking might not be a big deal, but if it's noticeable, it's better to visit a repair shop sooner rather than later. Ignoring it not only affects your driving experience but also wastes fuel.
As a car enthusiast, I think there are quite a few reasons for idle vibration: for example, a clogged air filter can cause unstable engine operation due to poor air intake; or issues with the ignition system, like excessively large spark plug gaps leading to uneven ignition; fuel pump or injector malfunctions causing unstable fuel supply; aging engine mounts with poor damping effect; and improper modifications, such as tampering with the exhaust system. I've researched these, and the key is regular throttle maintenance and replacing spark plugs, which can basically prevent vibrations. For severe vibrations, it's best to have a professional mechanic perform a computer diagnosis to prevent minor issues from becoming major problems.
