What causes engine idle vibration and no cooling after turning on the air conditioning?

[LaLillian]

Idle vibration and no cooling after turning on the air conditioning may be caused by the following reasons: 1. Severe engine carbon deposits: Carbon buildup in the engine is the main cause of car vibration. When there is excessive carbon deposit inside the engine, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in an overly lean mixture during cold starts. 2. Ignition system failure: Spark plugs are wearable parts that require regular replacement. The working condition of high-voltage wires and ignition coils can be determined using the vehicle's computer to assess the ignition system's status. 3. Fuel pressure issues: Abnormal fuel pump supply pressure or incorrect readings and poor performance of the intake pressure sensor can also cause vehicle vibration.