What is the normal RPM for an automatic transmission car during normal driving?

[DeJulia]

Normal RPM is generally around 2000, depending on actual conditions. The reasons for RPM increase and the hazards of unstable idle speed are as follows: Reasons for RPM increase: Cold start, low water temperature, battery discharge, air conditioning cooling. Hazards of unstable idle speed: If the car's idle speed is too high, check whether the intake manifold is loose or leaking, which will significantly increase fuel costs and also increase engine carbon deposits. If the car's idle speed is too low, there is a safety hazard of stalling at any time while driving. If the car's idle speed fluctuates, it may be due to spark plugs or ignition coils not working, causing the engine pistons to malfunction and resulting in severe shaking.