2011 VOLKSWAGEN PASSAT Wheels Problems

AN EMAIL I SENT TO DARCARS/ SILVER SPRING: IN JUNE OF 2016, I NOTICED MY CAR "PUTTERING" AND ALMOST STALLING OUT. A FEW DAYS LATER, MY ENGINE LIGHT COMES ON. I IMMEDIATELY CHECK THE OIL LEVEL, WHICH WERE GOOD. I THEN BELIEVE THERE TO BE AN ISSUE WITH THE MUFFLER, OR MANIFOLD. IN JUNE OF 2016, I BROUGHT MY CAR IN TO DARCARS DUE TO THE ENGINE LIGHT BEING ON. WITHIN A COUPLE HOURS, I WAS TOLD THERE WAS AN ISSUE WITH A VALVE (UNCLEAR INFORMATION PROVIDED BY THE RECEPTIONIST) UNDER THE HOOD. THE ACTION PROVIDED WAS UNDER WARRANTY, SO I HAD TO PAY NOTHING. I GOT MY CAR BACK THE SAME DAY...ENGINE LIGHT OFF, AND I DROVE HOME A FEW DAYS/WEEKS LATER, THE ENGINE LIGHT CAME BACK ON. I RETURNED TO DARCARS, AND TOLD THEM THE LIGHT WAS ON AGAIN. THIS WAS AROUND AUGUST 2016. THE RECEPTIONIST, TOOK THE...