My 05 shutting down need help

[Dwall870]

I have an 05 duramax and off and on my truck would shut down and can't move it. Check engine light comes on and truck is knocking bad! For some odd reason I undo gas cap and start truck it runs good till next time. For last month it's been doing it alot more and gas cap thing isn't working. I heard that my number 2,7 injector plugs could be bad bu t figure I ll ask what the forum thinks. Please help me on this one.

 

[mechman3]

Have you looked to see if the #2 and/or #7 injector wire connector has been replaced? My guess is that is the issue. However, after saying that the code from the truck would be a great help in diagnosing. Connectors are easy to replace but get the codes.