What was found
GE CNR 20220520046 #2 ENG (S/N 896912) EXPERIENCED ERRATIC SHIFTS IN CORE VIBRATIONS AT CRUISE AND TAKEOFF. PERFORM T/S PER DEFER TAB. #PRI2. GROUNDED - YES. ACCOMPLISHED AAVM SYSTEM BITE TEST, "N2 TACHO LOSS E2" LOGGED REF. B737-800 AMM 77-31-00-970-803-F00 AND B737-800 FIM 77-31 TASK 801. TROUBLESHOOT PER FIM 77-31 TASK 805, B737-800 WDM 77-31-21 AND 77-12-21, FOUND T422 , N2 SPEED SENSOR INTERNAL RESISTANCE FAILS. REMOVED AND REPLACED #2 ENGINE N2 SPEED SENSOR REF AMM 77-11-02/401. RUN THE ENGINE AT IDLE-POWER AND PERFORMED LEAK CHECK, NO LEAK NOTED. EEC BITE CHECK GOOD. NO FAULT NOTED AT THIS TIME. ETOPS SIGNIFICANT SYSTEM GROUND VERFICATION GOOD.