As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE N1 FLUCTUATES FROM IDLE THRUST TO 10 % N1 WHEN THRUST LEVERS ARE AT IDLE DURING DESCENT NORMAL UNCOMMANDED FLUCTUATION 43-53% N1. RESECURED ELECTRICAL CONNECTOR ON N1 SPEED CARD SENSOR REF AMM 77-12-01 AND IDLE RAN OK AT THIS TIME IAW AMM 71-00-00.