The optimal idle speed for an automatic transmission engine varies depending on the model and manufacturer of the vehicle. However, a typical range is:
* Gasoline engines: 650-800 rpm
* Diesel engines: 750-900 rpm
Idle speed is the speed at which the engine turns when the car is in park or neutral and does not press the gas pedal. This is an important parameter that affects performance, fuel economy and emissions.
Low idle speeds can cause the engine to run rough, and too high idle speeds can lead to increased fuel consumption and engine wear. Therefore, it is important to maintain engine idle speed within manufacturer specifications.