What was found
BWD/DFW - FLT 1230 - ON TAKEOFF ROLL JUST BEFORE V1, EXPERIENCED A POWER DROP IN LT ENGINE AND ACFT YAWED TO THE LEFT. ABORTED TAKEOFF AND RETURNED TO GATE WITH NO FURTHER ABNORMALITIES NOTED. MAINTENANCE CONTROL DISPATCHED FROM DFW AND ADJUSTED SCREW 'X' ON LT ENGINE ONE FULL TURN AND ADJUSTED THE FUEL FLOW 20 CLICKS. MAINTENANCE AND FLIGHT CREW PERFORMED GROUND RUNS AND FULL POWER ASSURANCE RUNS. ALL INDICATIONS WITHIN PARAMETERS. AIRCRAFT RELEASED TO SERVICE.