What was found
DURING A MAINTENANCE CHECK FLIGHT, THE AIRCRAFT LOST ENGINE POWER APPROXIMATELY 2-3 MILES FROM AIRPORT ON APPROACH. ACFT WAS ABLE TO LAND UNEVENTFULLY ON ANOTHER RUNWAY AT THE SAME AIRPORT. PILOT STATED HE WAS APPROACHING AIRPORT FROM WEST AND WAS DIRECTED TO ENTER RT DOWNWIND TO RWY 23. ENGINE SHUTTERED, VIBRATED AND WHEN HE ATTEMPTED TO INCREASE POWER HE DISCOVERED THE ENGINE HAD LOST POWER. SWITCHING TANKS AND TURNING BOOST PUMP ON AND OFF HAD NO EFFECT. PILOT REQUESTED RWY 10 AND LANDED WITHOUT INCIDENT. WHEN ATTEMPTING TO RUN THE ENGINE ON THE GROUND, IT SEEMED TO HAVE A FUEL STARVATION PROBLEM EVEN AT IDLE SPEEDS. DISCOVERED THE ENGINE DRIVEN FUEL PUMP PRESSURES HAD DROPPED OUT OF TOLERANCES. FUEL PUMP WAS REPLACED WITH AN OVERHAULED PUMP AND THE PROBLEM PUMP RETURNED TO MFG AS A CORE.