What was found
AIRCRAFT WAS GROUNDED: CLIMBING THROUGH 10,000 FT ENG1 N1 84.3, ENG2 88.8. CLIMB THRUST, SHOULD HAVE BEEN 88.9 ON BOTH ENGINES.,CLIMBING THROUGH 11,000FT ENG1 N1 81.8, ENG2 N1 89.4 CLIMB THRU,ST SHOULD HAVE BEEN 89.5,TRIED MANUAL THRUST TO RECOVER CLIMB THRUST BUT WAS UNSUCCESSFUL, DECESION MADE TO RETURN TO MSY. MAINTENANCE FOUND PS3 SENSE LINE CHAFED THROUGH. REPLACED #1 ENGINE PS3 SENSE LINE IAW AMM 72-00-00.