My 2004 Grand Prix has started acting up lately. When I start it for the first time each day and put it into drive or reverse nothing happens for 1-3 minutes. Then when the transmission does engage it seems fine the rest of the day.
I have changed the fluid and filter but no change in the transmission response. Any ideas what can cause this. Is it the Pressure control or more. I would like to have supplies on hand before taking it apart.

I'm sure your input piston seal is leaking until the transmission warms up. Pretty common problem with the 4T65E transmission. I had to replace the seal on my dads buick for the same issue. Unfortunately you need to tear down most of the transmission to replace the seal.

Thanks for the information. I will tear into it this weekend.

Good luck! They guy in the YouTube videos repairs the transmission in the car by lowering the cradle quite a bit on the drivers side. I decided to fully remove the transmission when I repaired my fathers car.

I found the issue to be exactly as described above. I do have one question although. The oil has in my opinion has too much silver (metallic looking). Would the clutches cause that much silver? I have not found anything else that seems to wearing.
Thanks,

Could be, it also could be some of the final drive hard parts. I would consider tearing the rest of the way down and to a rebuild. You don't want that metal to start effecting things like the TCC.