2006 Pontiac G6 Please Help! - Pressure Control out w/no co

They do have problems with the pressure control soleniods, I do a lot of them for that reason. But they usually set a p1811 code.
If your getting a mass air flow code, I'd look into that also.
But I'd consider changing the PC soleniod.
Let me know how you make out.

Would you recommend checking the harness or any wiring before changing the PC? I read a bulletin about the wiring harness going bad and causing the same issues. In both cases however I read that it would throw a code. Any ideas as to what could cause this and not throw a code or why it would not throw one? Also, is it possible that the MAF code could be caused by the lack of controlled pressure, or vice versa?

I see the bulletin that you are talking about but it also states that you should have a code(s) p0742, p2761, p2764. The symptons are similar. But with any transmission repair, once you get it out and apart you always want to look at as much as you can while you have it down in front of you. All the harnesses and connectors, metal debris, etc. Because you don't want to take it apart twice.
So yes, I would check the harness, but I'd more than likely put a PCC soleniod in it also as I have it apart.

The MAF can give you a lot of driveabilty issues, but for it to give you a trans problem the engine would have to be running bad makeing the hard shifts or be an electrical problem on the circut that goes to the MAF and the trans.

Hope all this helps. Let me know how you make out.