NHTSA Complaint #11151017 — 2011 GMC SIERRA 1500

I WAS ACCELERATING ON TO THE FREEWAY WHEN I HEARD A POP THEN THE ENGINE LIGHT CAME ON. THE VEHICLE STARTING KNOCKING AND LOST POWER. I CALLED ONSTAR AND THEY GAVE ME THE CODE P0300: THE EMISSIONS SYSTEM IS NOT PERFORMING AS EXPECTED. AN ISSUE HAS BEEN DETECTED IN THE EXHAUST EMISSIONS SYSTEM WHICH MONITORS AND CONTROLS EXHAUST GASES RELEASED INTO THE AIR FROM THE ENGINE. IF THE VEHICLE IS CONTINUALLY DRIVEN WITH THIS LIGHT ON, THE EMISSION CONTROLS MIGHT NOT WORK AS WELL, THE VEHICLE FUEL ECONOMY MIGHT NOT BE AS GOOD, THE ENGINE MIGHT NOT RUN AS SMOOTHLY AND COULD LEAD TO FUTURE REPAIRS. I WAS TOWED TO GREINER GMC IN VICTORVILLE, CA. I WAS TOLD A LIFTER FAILED AND THE CAM SHAFT IS DAMAGED. I'M LOOKING AT $5800 IN REPAIRS.