What was found
LEFT ENGINE RAN SMOOTHLY & MADE APPROPRIATE POWER ON TAKEOFF/ CLIMB, BUT, N1,N2 & FUEL FLOW FLUCTUATED NOTICABLY DURING CLIMB( NOT SURE ABOUT FLUCTUATION ON TAKEOFF). GROUNDED - YES. PRESENT FAULT ON OBS 73-44632 FAN SPEED N1 SENSOR LOW TOOTH SIGNALIS INVALID IFIM G73-21-00-810-947 CALLS FOR PART POWER LEAK TEST REF AMM G71-00-00-710-801-G00. 76352 ACCOM.EEC TEST ENG #1 TEST PASS NO FAULTS RETURNED EEC TO NMC. REF IFIM 73-21-00-810-947 STEP B 1&2 . 80780 09\/26/2023PER TSR71503 4. REMOVED AND REPLACED N1 SPEED SENSOR IAW AMM 77-12-01. ACCOMPLISHED IDLE TEST. NOLEAK OR DEFECTS NOTED.