Cyl. 2,4,6 missfiring/ injectors not working Buick Enclave 2008 3.6

Ideas would be to perform testing using the proper fully functional diagnostic equipment capable for your vehicle and enlisting the use of a shop manual and wiring diagram to follow the proper troubleshooting flowchart for your concern. How have you verified the "injectors not working"? What diagnostic trouble codes have you retrieved? This is not something the typical "do it yourself" home mechanic can approach.