What was found
(CAN) CREW REPORTED ENGINE SURGING THROUGH 1,500 POUNDS OF TORQUE. SURGE WOULD NOT OCCUR UNLESS THE POWER WAS REDUCED BELOW 1,500 POUNDS TORQUE AND THEN ADVANCED THROUGH 1,500 POUNDS TORQUE. MAINTENANCE FOUND THE COMPRESSOR BLEED VALVE STICKING AT 1,500 POUNDS OF TORQUE. THE BLEED VALVE WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE.