What was found
WHILE ENROUTE , THE POWER LEVER WOULD NOT REMAIN IN FORWARD POSITION. PILOT ELECTED TO RETURN TO DEPARTURE. NO EMERGENCY DECLARED. MAINTENANCE TROUBLESHOT, AND FOUND LOW & HIGH IDLES EXCESSIVELY HIGH, POWER LEVER JERKS. REPLACED FUEL CONTROL. RIGGED, PERFORMED ADJUSTMENT, TEST AND GROUND RUNS. OPS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.