What is the idle speed of an automatic car?
2 Answers
The idle speed of an automatic car is between 1800 and 2000 RPM. RPM refers to the number of revolutions per minute of the engine crankshaft. The engine speed affects the number of power strokes per unit time or the effective power output of the engine. An automatic transmission does not require the driver to manually shift gears; the vehicle automatically selects the appropriate gear based on the driving speed and traffic conditions. The gears of an automatic car are: 1. D gear refers to the drive gear; 2. R gear refers to the reverse gear; 3. P gear refers to the parking gear; 4. L gear refers to the low-speed gear; 5. N gear refers to the neutral gear; 6. W gear refers to the snow/rain gear; 7. S gear refers to the sport mode driving gear.
The idle speed of automatic transmission cars generally ranges between 600 to 800 RPM, but this is not a fixed number. Based on my years of driving experience, it varies significantly across different models and environmental conditions. For example, my SUV's idle speed rises to around 900 RPM when the air conditioning is on in summer, while during cold starts in winter, it may go as high as over 1000 RPM, dropping only after the engine warms up. Unstable idle speed could indicate carbon buildup in the throttle body or sensor malfunctions, which should be addressed promptly. Observing the tachometer while driving is a habit of mine; if the RPM exceeds 800 and stays high, I worry about excessive fuel consumption. Automatic transmissions have slightly higher idle speeds than manual ones due to the load on the transmission, but the difference is minimal. I advise car owners not to worry too much—stable idle speed during normal driving is fine. If abnormalities occur, it's best to visit a professional repair shop to prevent major issues. In short, maintaining around 700 RPM is the most common comfort zone.
