As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING NORMAL OPERATIONS, THE ENGINE WOULD SPUTTER AND RUN VERY IRREGULARLY AT IDLE. AFTER ROUTINE IDLE SPEED/MIXTURE ADJUSTMENT THE ENGINE RAN PROPERLY. THIS ENGINE/FUEL CONTROL COMBINATION REQUIRES ADJUSTMENT OF THE IDLE SPEED/MIXTURE MORE OFTEN THAN TYPICALLY REQUIRED IN THE GA TYPE AIRCRAFT.