What was found
DURING CLIMB, ENG #1 EGT 75C WARMER THAN ENG #2 WITH RAPID FLUCTUATIONS +/- 10C. AT CRUISE ENG #1 EGT 40C WARMER THAN ENG #2 BUT STABLE. NO EXCEEDANCES NOTED, HIGH TEMP + FLUCTUATION ABNORMAL. GROUNDED - YES. ACCOMPLISHED #1 ENG EEC BITE IAW B737-800 FIM 73-00 TASK 801. FOUND FAULT CODES 73-31371, 77-20871. ACCOMPLISHED TROUBLE SHOOTING PER FIM 73-11 TASK 801 UPPER EGT SECTORS READING HIGH, ACCOMPLISHED EGT CLEANING OF #1 ENG REF AMM 77-21-00. INPUT MONITORING SHOWS NO ABNORMAL TEMP DIFFERENCES NOTED FOR T49.5 SENSORS. DEFECT CLEARED.