NHTSA Complaint #11395603 — 2012 GMC ACADIA

I HAVE 2 ONGOING ISSUES, 1ST IS THE CAR WILL BE DRIVING FINE THEN GET A CHECK ENGINE LIGHT AND HAVE A CODE FOR CYLINDER MISFIRE. CAR WAS AT DEALER MULTIPLE TIMES WITH ISSUE AND COULD NOT DUPLICATE WHILE UNDER EXTENDED WARRANTY. MYSTERIOUSLY THE INTAKE HAS TO COME APART AND BE REWORKED SINCE THE WARRANTY EXPIRED, AND STILL HAS SAME ISSUES. THE 2ND AND MORE CONCERNING ISSUE IS THE POWER STEERING. INITIALLY TOOK IN AND TOLD THE RACK AND PINION NEEDS CHANGED. STILL HAD SAME ISSUE AND TOLD POWER STEERING NOW NEEDS TO BE CHANGED, SO WE DID. SOUND AND STILL STIFF AFTER 2 RACKS AND 2 PUMPS. MECHANIC REFUSED TO WORK IT AGAIN. TOOK TO DEALER YESTERDAY. SAYS NEEDS NEW POWER STEERING PUMP. SO DEALER TOOK FOR A TEST DRIVE AND SAID IT'S STILL DOING IT AND NEEDS ANOTHER RACK AND PINION. AT WHAT POINT IS GMC THAT HAS A KNOWN SAFETY ISSUE WITH STEERING GOING TO FIX THIS ISSUE. I CAN'T KEEP THROWING MONEY AT THIS THING AND I CAN'T FEEL UNSAFE IN IT. WHAT CAN I DO?