Why is the idle speed unstable when Toyota Crown washes the throttle?

This is normal, just run for a few days.

The reason for this is the following：

(1) After washing the accelerator, the oil stain in the accelerator is gone.

(2) The return position of the air door has changed.

(3) The throttle position sensor signal has also changed.

(4) The engine control unit has no automatic adjustment signal.

Therefore, the idle speed is unstable, and the engine will automatically adjust after self-learning.

Engine idling instability refers to the change of gas acting force in the cylinder, which causes the imbalance of power in each cylinder, resulting in the inconsistency of horizontal component of each piston during the power stroke, resulting in the imbalance of engine lateral shaking torque and engine shaking. Engine idling instability is the most common fault in engine maintenance. If the diagnosis idea is incorrect, it will prolong the maintenance time and reduce the work efficiency.