I pulled the intake manifold off and found that the EGR valve and manifold
port to the EGR solid plugged. I have the nut off the EGR valve but it wont
come apart. Must I unfasten what looks like a hex fitting into the valve
body?

Gotta get the oil trap out and see what that looks like.
after I get some more degreaser and brake cleaner, It's
like working in a coal mine under there, even though it was
just powerwashed. All that stuff is hidden, and covered with black slime.

What else should I do with the intake manifold off, one write up
suggested doing something with the knock sensor?

Thanks, Bill