What is the solution for Civic's idle vibration when the air conditioning is on?

[LaLyla]

Causes and solutions for Civic's idle vibration when the air conditioning is on: 1. Severe engine carbon deposits: The most common cause of car vibration is dirty throttle or excessive carbon deposits in the fuel injectors. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold start injector is largely absorbed by the carbon deposits, resulting in a lean mixture during cold starts and making it difficult to start. In this situation, the engine will only start easily once the carbon deposits are saturated with gasoline. After starting, the gasoline adsorbed on the carbon deposits is sucked into the cylinder by the engine's vacuum force for combustion, making the mixture too rich. The engine's combustible mixture alternates between lean and rich, causing idle vibration after a cold start. The solution is to clean the fuel system and check if the idle control valve has carbon deposits, which should be cleaned. 2. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor ignition system performance or weak spark plug firing can also lead to such issues. The solution is to check if the spark plugs have excessive carbon deposits and replace them if necessary. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle, replaced the fuel filter, and spark plugs but still experience idle vibration, it is recommended to visit a 4S shop to check the fuel supply pressure and intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can cause body vibration. The solution is to check the fuel pressure and replace components if necessary. 4. Aging engine components: Car vibration can also be related to worn engine mounts. Engine mounts are part of the engine's vibration damping system, responsible for absorbing minor vibrations during engine operation. If the engine mounts are faulty, these vibrations will transfer to the steering wheel and cabin, causing idle vibration, and they need to be replaced.