What was found
EVV - FL 777 - FLIGHT WAS CRUISING AT FL 310 WHEN THE NR 2 ENGINE CAME BACK TO 50 PERCENT POWER OR 2,000 LBS FUEL FLOW. CREW TURNED ON ENGINE HEAT WITH NO EFFECTS ON ENGINE. CREW TURNED ON FUEL HEAT, NR 2 ENGINE WENT PAST NORMAL N1 AND N2 INDICATIONS. CREW HAD NO CONTROL OF THE ENGINE AND SHUT DOWN THE NR 2 ENGINE. CAPTAIN DECLARED AN EMERGENCY AND DIVERTED TO EVV. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. TOTAL SINGLE ENGINE TIME WAS 10 MINUTES. MAINTENANCE REPLACED THE NR 2 ENGINE FUEL CONTROL UNIT AND FUEL PUMP. LEAK CHECK AND ENGINE TRIM RUN GOOD. REFERENCE USAASB96214.