Engine Idle Speed

[GerryO]

The only times that the engine idle speed drops as the engine warms up to or at full temperature is when the car is at a FULL stop, in gear with the brake applied.

If the car is driven non-stop for even 20+ miles and without the engine idle speed having dropped to its' low point, it still requires a few seconds at a FULL stop, in gear with the brake applied to drop the engine idle speed to its' 650 rpm setting.

Once the engine idle speed has dropped to its' low point and as long as the engine is still warm, engine rpms will return to their low point. Engine idle speed is stable at all times.

Why don't the inputs (temperature, TPS, etc) that determine engine idle speed take affect while the car is being driven?