Very frustrated, and in need of desperate help. I have a 2010 GMC Acadia. Service engine light on, and diagnostic is coming back with several misfire codes. Replaced battery, starter, all 6 coils, spark plugs, 2 of the 3 O2 sensors, mass air flow sensor and it still wont start. The other day I was stopped at a stop light, and when it became green, I started to take of and the Acadia just turned off out of now were and I havent been able to get it to start ever since. We have tried the process of elimination, and now it is getting to expensive for me to keep replacing parts. Can someone please help me try to figure this out?