2011 Chevrolet Suburban 2500

FROM 2017-PRESENT ENGINE LIGHT IS ON AND HAS CODE P0455. WHILE DRIVING DOWN THE ROAD VEHICLE DRIVES A BIT ROUGH AND ON AT LEAST 8 OCCASIONS IT HAS LOST POWER WHILE DRIVING DOWN THE ROAD. ALMOST FEELS LIKE ITS GOING TO SHUT OFF. THREE SMOKE TESTS WERE DONE, ONE AT A CHEVROLET DEALER IN 2017. SO FAR AUTO REPAIR SHOPS HAVE REPLACED 1)GAS CAP, 2) PURGE VALVE 4 TIMES, 3) FUEL SENSOR ABOVE FUEL TANK AND WE DIY REPLACED CARBON CANISTER AND VENT VALVE SOLENOID. STILL THE PROBLEM PERSISTS.

ENGINE LIGHT ON VEHICLE RUNS ROUGH/SPUTTERS WHILE GOING DOWN ROAD. TOOK TO 3 MECHANICS INCLUDING GM DEALER. ALL STATED EMISSIONS CODES. 1ST MECHANIC REPLACED PURGE VALVE. LIGHT CAME BACK ON. SAME MECHANIC DID SMOKE TEST AND REPLACED PURGE VALVE STATING IT MUST HAVE BEEN FAULTY. LIGHT CAME BACK ON. CHEVY DEALER REPLACED PURGE VALVE. LIGHT CAME BACK ON. LAST MECHANIC REPLACED FUEL SENSOR. LIGHT CAME BACK ON AND THEY STATED IT NOW NEEDS A PURGE VALVE. IN ADDITION, DASH STABILITY LIGHT COMES ON BUT DOES NOT GO OF WHEN BUTTON PUSHED. DVD PLAYER ALSO SEEMS TO BE CONSTANTLY WHIRRING. HOWEVER, MAIN CONCERN IS STILL THE ENGINE LIGHT THAT NO ONE SEEMS TO KNOW HOW TO FIX AFTER I'VE SPENT OVER $1K FOR SEVERAL PURGE VALVES, SMOKE TEST AND FUEL SENSOR. THESE PROBLEMS ONGOING FOR OVER A YEAR AND NO ONE IS ABLE TO RESOLVE!