What was found
IN CRUISE FLT AT FL370 WHEN THROTTLE IS RETARDED TO APPROX 1.13 EPR ON THE RT ENGINE, THE ENGINE SURGES. NOTED + - 3 EPR, + - .5 N1, ALSO RT PAC DUCT PRESSURE CYCLES FROM LOW TO HIGH FLOW 42 - 25 PSI. IN SUMMARY RT ENG SURGES AT LOW POWER SETTING. REMOVED RT FMU AS PER AMM 73-21-01-004-002. 17944 7/1/17. INSTALLED RT FMU PER AMM 73-21-01. OPS CHECK, LEAK CHECK GOOD. OK FOR SERVICE. INSTALLED RT FMU PER AMM 73-21-01. OPS CHECK, LEAK CHECK GOOD. OK FOR SERVICE.