What was found
ENGINE START & TAXI CHECKS WERE NORMAL. A ROLLING TAKEOFF WAS PERFORMED TO COMPUTED EPR'S. ALL ENG PARAMETERS WERE NORMAL DURING TAKEOFF ACCELERATION UNTIL A DROP IN THE LT ENG EPR TO APPROXIMATELY 1.9. THE LT ENG THRUST LEVER DID NOT RESPOND TO AN ATTEMPT TO INCREASE POWER & I THINK LP, HP LT ENG TAPES WENT OVER RANGE. THE TAKEOFF WAS CONTINUED, FLAPS SET TO 10 DEGREES. I HEARD ENG DECELERATE DURING LEFT TURN OF THE DEPARTURE PROCEDURE AT APPROXIMATELY 800 TO 1000 FEET. A CLIMB TO TRAFFIC PATTERN ALTITUDE & A RETURN TO LANDING WAS ACCOMPLISHED WITH THE LT ENG UNSECURED AS I WAS UNABLE TO DETERMINE IF IT WAS NOT PRODUCING POWER USING THE ENG INDICATIONS & THE SHORT TIME BETWEEN TAKEOFF & LANDING. AT NO TIME WAS THERE A FIRE WARNING OR ANY INDICATIONS OF FIRE. THE LT ENG START LEVER WAS SECURED DURING TAXI IN.