What is the appropriate idle speed for an automatic transmission?
2 Answers
An idle speed of 500 to 850 RPM is appropriate for an automatic transmission, while the instantaneous idle speed during a cold start is around 1500 to 2000 RPM per minute. The characteristics of an automatic transmission car are: 1. Easy to operate, simple to learn, and easy to master driving techniques; 2. High driving comfort with relatively smooth gear shifting; 3. High safety factor, reducing driver fatigue. The gears of an automatic transmission car include: 1. P gear is the parking gear, used for long-term parking of the vehicle; 2. R gear is the reverse gear, engaged when the vehicle needs to move backward; 3. N gear is the neutral gear, engaged when the vehicle is parked for a short time without turning off the engine; 4. S gear is the sport mode, making the vehicle drive more sporty; 5. M gear refers to the manual mode, where the driver manually completes the gear shifting when the gear lever is engaged in M gear.
For automatic transmission vehicles, maintaining an idle speed between 700 and 800 RPM when parked is generally ideal. This range ensures smooth engine operation and prevents shaking or stalling. If the idle speed is too low, such as below 600 RPM, the engine may become unstable; if it's too high, exceeding 1000 RPM, fuel consumption will increase. I've driven many automatic cars, and especially during cold starts, the idle speed tends to be higher initially, around 900 to 1000 RPM, then returns to normal once the engine warms up. During regular driving, if the air conditioning is on or there's a heavy electrical load, the idle speed may rise slightly, which is normal. However, if the idle speed frequently fluctuates or becomes unstable, it could indicate a dirty throttle body or a faulty sensor. I recommend getting it checked promptly to avoid bigger issues that could affect driving comfort. Keeping an eye on the tachometer on the dashboard and making it a habit can help save fuel and extend your car's lifespan.
