We have a 2011 Enclave CXL 2WD. It has 110K miles. Like a month ago it reduced speed on highway and showed "Reduced engine power", when my wife took it to Autozone for codes it showed several misfires. I researched the issue online and ended up cleaning the throttle vary and it worked perfect. The engine light disappeared when I reset the computer. No more issues until 3 weeks ago when were driving on the highway and the same situation happened. I took it to Autozone and the code was "misfire on injector 5". After I kept driving it the engine light disappeared by itself and the car was working fine until today. I was driving very slowly on the park and the same message came to the board, the car lost power and a lot of white smoke. I took it to Autozone and the code read misfire on injectors 1,3,5 and issue with fuel pressure regulator. Does anybody has an idea what could be the issue with this car?