What to Do When the Car Suddenly Shakes at Idle Speed?
2 Answers
The reasons for sudden shaking of the car at idle speed are as follows: 1. Inappropriate air-fuel mixture causing shaking. If the air-fuel mixture ratio in the car engine compartment is not accurately adjusted, the car is prone to shaking. In closed-loop control vehicles, the minimum operating temperature of the oxygen sensor is 370 degrees Celsius. If the car has just been started, the temperature in the exhaust pipe does not reach 370 degrees Celsius, so the oxygen sensor does not work. At this time, the ECU makes a misjudgment, and its control over the air-fuel mixture and ignition timing through the actuators has errors, thereby reducing the car's power output and causing shaking. 2. Low ignition energy causing shaking. The first problem a car faces during a cold start is low temperature. The temperature inside the engine is insufficient, and the temperatures of both fuel and lubricating oil are not enough. Therefore, more fuel should be injected during a cold start to meet the power requirements. The larger the spark plug gap, the smaller the ignition energy. At low temperatures, fuel atomization is poor, and the fuel requires higher ignition energy. After prolonged use, the spark plug's ignition gap tends to increase, leading to a decrease in ignition energy, which affects power performance and causes the car to shake.
Sudden engine idling vibration can indeed be alarming. When I encountered this issue last time, I first pulled over to inspect the engine. The most common causes are worn spark plugs or failing ignition coils, leading to incomplete combustion. Fuel system problems like unstable fuel pump supply or clogged fuel injectors can also cause vibrations. For a quick check, open the hood to look for obvious oil leaks or loose wiring. If the vibration persists, avoid driving to prevent stalling or engine damage – it's best to seek professional diagnosis. Carbon buildup in the throttle body can also disrupt air intake, so cleaning every 20,000 km is recommended as prevention. Never overlook these maintenance details for safe driving.
