What was found
AIRCRAFT WAS GROUNDED: ENGINE #2 ROLLED BACK TO APPROXIMATELY 50 % N1 FOR 3-5 SECONDS, THEN RETURNED TO NORMAL ON CLIMBOUT. EMERGENCY DECLARED; FLIGHT RETURNED TO PHX LANDING SAFELY. MAINTENANCE REPLACED ENGINE #2 PRESSURE REGULATING AND SHUTOFF VALVE (PRSOV) PER AMM 36-11-04 (AALA202305102732), HIGH PRESSURE SHUTOFF VALVE (HPSOV) PER AMM 36-11-07 (AALA202305120711), PS3 LINE (AALA202305129630), AND PS3 LINE #2 FITTING (AALA202305121845). ACCOMPLISHED SATISFACTORY CHECKS.