What was found
DEFECT - BAFFLES IN MUFFLER ARE MISSING. APPARENTLY, PARTIALLY BLOCKING EXHAUST. OCCURRENCE - POWER LOSS AT 6,500 FEET, 75 PERCENT POWER AT CRUISE. ENGINE RAN ROUGH AND LOSS OF POWER. COULD NOT DUPLICATE OCCURRENCE ON GROUND. SUBMITTER STATED THIS PART HAS NOT BEEN CHANGED SINCE PURCHASED. HARD TO DETECT PREMATURE FAILURE.