The likely cause of your F 350 having an idle surge is due to eaither a bad Injector pressure Regulator or a bad Injector control pressure sensor. See attachment for testing. In most cases it is a bad Injector pressure regulator (the orings come apart)
Boost is about 10 12 lbs. Let me know what you come up with when he gets back.
Yes I would have a look at the waste gate.