What causes unstable idle speed and shaking in a car?

[VanNadia]

Here are the reasons for unstable idle speed and shaking in an engine: 1. Aging rubber components: The rubber parts inside the engine mounts and transmission mounts have aged. 2. Improper air-fuel mixture: The air-fuel mixture ratio in the car's engine compartment is incorrect. 3. Carbon deposits: Carbon buildup on the engine's valves and intake passages can absorb a significant amount of fuel, causing some of the sprayed air-fuel mixture to be absorbed by the deposits, reducing the car's power and causing vibrations. 4. Malfunctioning coolant temperature sensor. 5. Incorrect air-fuel mixture ratio in the car's engine compartment. An engine is a machine that converts other forms of energy into mechanical energy, including internal combustion engines, external combustion engines, jet engines, and electric motors.