What Causes Car Vibration When Idling with AC On?
2 Answers
Car vibration when idling with the AC on can be attributed to the following reasons: 1. Carbon buildup: The engine may have severe carbon deposits. Carbon buildup in the engine is a primary cause of car vibration. The solution is to regularly clean the fuel system, inspect the idle control valve, and clean the throttle body. 2. Ignition system: There might be a fault in the ignition system. Spark plugs are wear-and-tear components that require periodic replacement. If excessive carbon buildup on the spark plugs or excessively large ignition gaps are observed, replacement is necessary. 3. Fuel pressure issues: It is essential to check whether the fuel supply pressure and intake pressure sensors are functioning correctly. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can both cause car vibration.
I've encountered many cases of vehicle shaking when idling with the AC on. The main reason is that the AC compressor adds significant load to the engine, especially noticeable at low RPM. During repairs, I often hear owners complain about this issue. Upon inspection, it's frequently due to worn engine mounts - when the rubber components crack, they can't absorb the extra vibrations, leading to noticeable shaking. Another potential culprit is a stuck or unbalanced AC compressor, which directly transmits vibrations throughout the vehicle body. Additionally, worn spark plugs or excessive carbon buildup in the idle control valve can cause unstable engine idling. When the AC turns on and increases the load, the RPM drops, making the whole car tremble. Regular maintenance should include checking engine mount condition and carbon deposit cleaning. Otherwise, severe shaking could damage chassis components and affect driving safety. It's always better to get a professional evaluation early on.
