What was found
GENERAL - APPLIES TO ALL AIRCRAFT. DURING TROUBLESHOOTING FUEL SYSTEM FOR LEFT AND RIGHT TANK, UNEVEN FUEL FLOW, FOUND PIECE OF AFTER-MARKET 6 INCH ROUND GAS TANK OCTANE RATING PLACARD/STICKER LODGED IN FUEL LINE AT SUMP CHECK VALVE PARTIALLY RESTRICTING FUEL FLOW FROM RIGHT TANK. SMALL PIECE OF VINYL PLACARD APPARENTLY CHIPPED OFF BY FUELING NOZZLE DURING RE-FUEL. SUBMITTER SUGGESTS PLACARDS/STICKERS BE APPLIED FAR ENOUGH AWAY FROM TANK INLETS TO PRECLUDE BEING CHIPPED BY FUELING NOZZLE AND ENTERING SYSTEM.