Wagoneer L6-242 4.0L VIN M FI (1988)
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If the idle speed changes according to the position of the switch, the idle speed stepper motor is functioning properly. Disconnect the
exerciser tool and reconnect the idle speed stepper motor electrical connector to the stepper motor.
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If the idle speed does not change when the switch position is changed, leave the exerciser connected, turn the ignition switch OFF, and
proceed to step 7.
7.
Remove the idle speed stepper motor from the throttle body.
CAUTION:When checking the operation of the idle speed stepper motor, removed from the throttle body, be careful that you do not extend the
pintle more than .250 in. If the pintle is extended further than .250 in, it may separate from the idle speed stepper motor. If the
pintle separates from the motor, it is necessary that the whole part be replaced.
8.
With the ignition switch OFF, switch the exerciser tool between HIGH and LOW, and observe the movement of the pintle.
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If the idle speed stepper motor pintle does not move, replace and retest as described in step 6.
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If the pintle operates properly, check the idle speed stepper motor bore in the throttle body for corrosion or blockage and clean as
necessary. Reinstall the stepper motor and retest. If no blockage is found, see manufacturers instructions for exerciser tool.
