What was found
DURING TAKEOFF ROLL, PILOT UNABLE TO GET PROPER N1 INDICATION REQUIRED FOR TAKEOFF & ENGINE THEN STARTED ROLLING BACK ON POWER. TAKEOFF ABORTED & AIRCRAFT STOPPED WITHOUT INCIDENT. MX INSPECTED ENGINE & PERFORMED A GROUND RUN, UNABLE TO DUPLICATE PROBLEM. DEEC (DIGITAL ELECTRONIC ENGINE COMPUTER) DOWNLOADED & CHECKED. DOWNLOAD INDICATED A MOMENTARY OVERTEMP ON ITT. NO OTHER FAULTS NOTED. MODIFICATION OF SDR A COMPLETE FUNCTIONAL CHECK OF SURGE BLEED VALVE PERFORMED & UNIT FOUND TO NOT PERFORM WITHIN SPECIFICATIONS. UNIT REPLACED PER SB TFE731-76-3072. ENGINE RUN & CHECKED ON GROUND.