What is the appropriate idle speed for an automatic transmission car?

[Gomez]

For an automatic transmission car, the normal engine idle speed is generally between 700-800 RPM. Unstable car idle speed can lead to the following hazards: 1. If the car idle speed is too high, check whether the intake manifold is loose or leaking. This will significantly increase fuel consumption costs and also lead to more engine carbon deposits. 2. If the car idle speed is too low, there is a safety hazard of sudden stalling while driving. 3. If the car idle speed fluctuates, it may be due to spark plugs or ignition coils not working properly, causing the engine pistons to malfunction and resulting in severe shaking. Additional information: During cold starts, low coolant temperature, weak battery, or when the air conditioning is on, the idle speed will automatically increase by 50-150 RPM.