What was found
EICAS MSG "R ENG EEC" DURING CLMB. CREW DECIDE TO PERFORM AN AIR TURNBACK, AIRCRAFT LANDED UNEVENTFULLY. AIRCRAFT GROUNDED BY MAINTENANCE.BITE SHOWN R-J2 UNPLUD'D. INSPECT EEC J2 PLUG, D4224P, D4246J. IT WAS TIGHTENED & NO DEFECTS NOTED. REMOVED AND REPLACED M591 AND R EEC, EEC GROUND TESTS GOOD IAW B767MM 73-21-04 AND WITH ENGINE RUN, NO DEFECTS NOTED.