What was found
DURING CLIMB, NR 2 ENGINE N1, FUEL FLOW, AND EGT BEGAN TO FLUCTUATE. FLUCTUATION CONTINUED DESPITE VARIOUS POWER SETTINGS OR IN A CONSTANT POWER SETTING. FLIGHT CREW RETURNED TO DEPARTURE AIRPORT. MAINTENANCE REPLACED THE FUEL FILTER, FUEL PUMP, HMU, AND T12 SENSOR. ENGINE HAD A BORESCOPE INSPECTION AND WAS FOUND OK. AIRCRAFT GROUND RUN AND LEAK CHECK OK.