Why does the engine idle shake every few seconds?
2 Answers
Car idle shaking is caused by engine carbon deposits, aging or carbon buildup in spark plugs, dirty engine throttle body, poor fuel flow, or ignition system failure. Engine carbon deposits result from various factors, but the primary cause is often poor driving habits. Relevant information about idling is as follows: 1. Introduction: Idling is an operational state of a car where the engine runs in neutral gear. The engine speed during idling is called idle speed. Idle speed can be adjusted by modifying parameters like throttle opening. Idling means the engine is "producing power without doing work." 2. Driving idle: When the car is in gear without pressing the accelerator pedal or when releasing the pedal during driving while maintaining minimum throttle opening, the engine speed matches parking idle speed - this condition is called driving idle.
My car also experienced a slight shudder every few seconds at idle before. At first, I didn't pay much attention, but later found out it was caused by excessive carbon buildup on the spark plugs leading to poor ignition. The old car had run 70,000-80,000 kilometers without changing the spark plugs, and carbon deposits clogged the electrodes, causing unstable engine RPM and resulting in shaking. Another possibility is a dirty intake system, such as oil contamination on the throttle body - a simple cleaning might solve it. If the fuel injectors are clogged, it can affect the regularity of fuel injection. I suggest first checking the spark plugs yourself to see if they need replacement; otherwise, take it to a repair shop for diagnosis to prevent the problem from escalating. ECU sensor failures can also cause this type of fluctuation. Remember to inspect the ignition system every 20,000 kilometers during regular maintenance to prevent minor issues from turning into tow-truck emergencies.
