I have 2011 Cadillac CTS coupe About 2 months ago I had a flashing check engine light while driving at about 70 mph on freeway. I pulled over and checked various features but couldn’t really see the problem. I started the car again and drove to the airport about 20’min away with the car hesitating, losing power but then it went away and kept coming back while driving there. When I got back from the airport, I drive the car back home, this time it ran normal. I parked the car at home. When I had the car checked it said it had a bad fuel pressure sensors and engine misfires on cylinder 3 and 6. I changed the fuel pressure sensor and the ignition coils and cylinder 3 and 6. Car ran fine for about a month and a half. Then I had the same issue of flashing check engine light and misfires while driving on the freeway at about 70 mph. Got it home and ran codes and it said misfire on cylinder 3 and 6 again. With faulty injector on 6. So I had the all the spark plugs changed, all ignition coils changed and then changed injector 1, 3 and 6. This is a 3.6 engine. Now I went to start it and the car starts but it makes a crazy sound underneath when starting and then while the car is in idle it flashes a check engine light and gives cylinder 1, 3 and 5 as misfires and says cylinder 5 has an injector problem. I m looking to go ahead and changed that injector but it wasn’t causing an issue at first. Could it be that the fuel rail is not properly on or something else? There is no smoke coming from the exhaust when I rev the engine up it recs up and runs smoothly but the misfire data is showing crazy misfire numbers on 1,3 and 5. In the 300 range just having the car on for about 5 min.