It was a turbo boost leak. You guys are my heroes!

I found the egr valve very loose. The intake manifold gasket bolts were also borderline so I snugged them up. The wastegate hose was cracked so I replaced it with fuel hose (is that the appropriate hose to use? That looks like what was on there.) Now the sound is gone!

I drove around with a gauge in the car showing the manifold pressure. My gauge only goes up to 10psi and when I floor the car the gauge just barely gets pinned. That sounds reasonably acceptable to me?

I have a little housekeeping to do now. I like the idea of cleaning the area as general good practice, but basically I'm home free now.

Thank you all for helping me out.

John