As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTS AT TAKE OFF ENGINES WERE AT 1.4 EPR AND A-C AT 20 KNOTS WHEN LOUD NOISE WAS HEARD AND ENGINE NR 2 HAD N1 AND N2 ROLLBACK, ENGINE RECOVERED AT IDLE AND REMAINED RUNNING ON RETURN TO GATE. REPLACED NR 2 ENG FMU PER AMM 73-22-50-000-010-B & 73-22-52-400-01 0-B. ACP'D ENG IDLE RUN LEAK CHECK. OPS AND LEAK CHECK GOOD.