[GAnOhio]

I suppose I should finalize this thread.
The project of replacing the upper intake manifold and the LIM gaskets went just fine. All that seems to be working out great. I am sure the cause of the massive vacuum at the oil cap was the bolt that was out; it was one of two that is on the inside and holds down the LIM. It was also what let oil residue up to the UIM and kinda created a mess. The inside of the throttle body was coated with oily buildup.
My seperate issue was the car dieing while sitting at idle after warm up. Or stumbled during acceleration. I replaced the crank pos sensor for that, but no change. It ended out being the MAF sensor. (Yes I used MAF sensor cleaner first.) Replaced the MAF sens and the car is running great.