What Causes Car Shaking at Idle Speed?
2 Answers
Reasons for car shaking at idle speed: 1. Severe engine carbon deposits: The gasoline sprayed by the cold start injector is largely absorbed by carbon deposits, resulting in an excessively lean mixture during cold starts and making it difficult to start. Solution: Clean the fuel system and check if the idle speed motor has carbon deposits that need cleaning; 2. Ignition system issues: Check the working condition of spark plugs, high-voltage wires, and ignition coils. Solution: Inspect if spark plugs have excessive carbon buildup and replace them if necessary; 3. Unstable fuel pressure: Check if the fuel supply pressure and intake pressure sensor are normal. Solution: Inspect fuel pressure and replace components if needed; 4. Aging engine components: Engine mounts are actually the shock absorption system of the engine, responsible for absorbing minor vibrations during operation. If engine mounts fail, these vibrations will be transmitted to the steering wheel and cabin, causing shaking at idle speed. Solution: Replace components.
Reasons for idle vibration, I've encountered this several times, mainly due to issues with the engine ignition system, such as aging spark plugs or faulty ignition coils. If spark plugs have been used for too long, the electrode gap becomes too large, causing misfires in certain cylinders and unstable engine RPM. There's also the matter of the fuel system; if the fuel injectors are clogged, uneven distribution of the air-fuel mixture can cause the idle to jump erratically. Don't overlook engine mounts or suspension components either. When the rubber deteriorates, it can't absorb vibrations, making the car feel like it's dancing. Faulty mass airflow sensors are also common, as improper air intake can make the engine struggle to breathe. These issues need to be checked promptly to avoid affecting driving safety. I recommend trying to replace the spark plugs first; if that doesn't work, take it to a professional shop.
