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When you unplug the IAC connector, the idling rpm would go up 1200 to 1400 as the valve is returned to the preset fail safe condition.
The low idling speed is due to insufficient air getting into the intake manifold. You can increase the idling speed by turning the idle adjust screw anticlockwise, adjust 1/4 turn at a time and wait for idling speed to stabilise before turning screw again. If it is not stable, clean the throttle body and IAC valve and readjust the idling speed.
Wednesday, February 4th, 2009 AT 7:21 AM