As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS FROM SHORTLY AFTER T/O UNTIL 18,000 LEFT ENGINE COMMANDED THRUST WAS 2-3% BELOW N1 COMMANDED THRUST SECTOR. GAP SLOWLY DECREASED UNTIL ALL NORMAL AT 18,000 FT. MAINTENANCE PERFORMED ENGINE ACCELERATION CHECK IAW AMM 71-00-00. BOTH ENGINES SPOOLED UP QUICKLY AND THROTTLES ALIGNED. NO FAULTS NOTED AT THIS TIME.