What was found
DURING DESCENT, ON THE ARRIVAL TO MIA, L & R ENG CONTROL STATUS MESSAGES. RIGHT ENGINE WOULD NOT ACCELERATE FROM IDLE. DECLARED EMERGENCY AT APPROX. 1930Z AND LANDED AT MIA. AFTER LANDING L & R ENGINE CONTROL EICAS MESSAGES APPEARED. MIA FIRE DEPARTMENT CHECKED A/C, EVERYTHING LOOKED NORMAL. REMOVED AND REPLACED M644EEC DISCRETE PRINTED CIRCUIT CARD, PER B767-300 AMM 73-21-11 AND REMOVED & REPLACED RIGHT ENG HMU IN REF WITH B767 AMM 73-21-14. OPS CHECK OK. NO LEAKS. A/C REMAINS NO ETOPS AND RETURNED AC TO SERVICE.