As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN DUE TO ENGINE 3 NOT DEVELOPING FULL CLIMB POWER 4% LESS N1 @ 10000 & 7% LESS AT 35000. ENGINE 3 EGT, N2 & FF CONFIRM POWER LOSS. ENGINE 3 "T" WOULD NOT ADVANCE INTO THE "V" EVEN WHEN GOING TO THE GIRT BAR. CORRECTIVE ACTION: ECU 3A & 3B CURRENT FAULT T/R L/H RVDT ADJUSTED POSITION TRANSDUCER (TR) PER AMM 78-34-01. PERFORMED HIGH POWER ENGINE RUN AND ALL PARAMETERS NORMAL PER AMM 71-00-00.