"My tech is pretty sure the multi-plug and the pipe is back on the actuator on the turbo"
I have had a few of these where the soft rubber elbow where the vac pipe attaches to the vac capsule has split, giving intermittent boost problems. You can easily check this with mityvac from electrovalve end of the pipe. Make sure the pipe/capsule is holding vacuum. Is it possible that when disturbing this pipe to replace turbo that this failed completely? (as it's not easy to see and a character building experience to get to!) Worth a look perhaps. All the best Phil.