What Causes Idle Vibration When the Air Conditioner is On?

[SanJoseph]

Reasons for idle vibration when the air conditioner is on are as follows: Ignition System Issues: Spark plugs have a limited lifespan. If the spark plugs have been used for a long time, they may not fire properly, leading to unstable idle speeds. Therefore, it is essential to inspect the ignition system, including the spark plugs, to determine if they need replacement or if there is excessive carbon buildup. If such issues are found and are causing the idle vibration, the spark plugs should be replaced or cleaned promptly. Throttle Body Needs Cleaning: The proper functioning of the throttle body directly affects the engine's performance. During vehicle operation, carbon deposits can accumulate in the throttle body. Excessive carbon buildup can obstruct normal air intake into the engine, resulting in insufficient engine power to drive the compressor or barely managing to do so. In such cases, idle vibration may occur when starting the car and turning on the air conditioner. Therefore, it is crucial to check the throttle body for cleanliness and clean it if necessary.