What was found
DURING CLIMB, NR 4 ENGINE, EGT VERY ERRATIC, FLUCTUATES BETWEEN 200 DEGREE AND 500 DEGREE, ON LANDING AT MIAMI AND TAXING AT IDLE, POWER ON NR 4 ENGINE, EGT STRUCK AT 180 DEGREE. REMOVED AND REPLACED NR 4 EGT INDICATOR RAN ENGINE AT BLAST FENCE, NO DEFECTS NOTED IAW 77-20-0.