As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 3005 - IN CRUISE FLIGHT TO BMI, THE ENGINE INDICATIONS FOR THE NR 1 ENGINE BEGAN TO FLUCTUATE WITH THE ECU ON. THE CREW TURNED OFF THE ECU AND THE INDICATIONS STABILIZED. THE AIRCRAFT RETURNED DTW. MAINTENANCE REPLACED AN ENGINE TRIM SWITCH. ALL SYSTEMS OPERATED SATISFACTORILY. (M)