09 Silverado 1500 4.8 Dtc p0171 p0174

[Cali-fornia]

Truck has 140k miles it runs good for the most part idle can be rough at cold start but smooths out in seconds. Have looked at most of the possible areas that seem to cause this code pcv, o2 sensors, maf. My question is that while I was inspecting areas around to maybe detect a vacuum Leak , I  noticed the intake manifold Have a very noticeable gap from the top and bottom almost as if it were beginning to come apart ? Is this common with these ? Can this be source of codes?