As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) UPON PERFORMING A GROUND RUN FOR AN ENGINE REPLACEMENT AND UPON THE APPLICATION OF FULL POWER THE ENGINE RESPONSE WAS GOOD, BUT IN ATTEMPT TO DECREASE ENGINE POWER THE ENGINE WOULD NOT RESPOND TO THROTTLE INPUTS. IT WAS APPROXIMATELY 30 SECOND TO A MINUTE BEFORE THE ENGINE POWER STARTED TO DECREASE TO NORMAL IDLE SPEED. INSPECTION OF ENGINE AND RIGGING REVEALED NO PROBLEMS. THE FUEL CONTROL UNIT WAS REPLACED AND A GROUND RUN CARRIED OUT WITHOUT THE RECURRENCE OF THE DEFECT.