I'm curious as to exactly what that means.
If they removed the PCM from the truck and bench tested it with a standalone power supply, with nothing else attached, and it was still intermittently dropping coms with the scan tool, then I'd be inclined to accept that a mosfet had failed in the PCM.
But if they left it in the truck and connected to the trucks harness connectors, the external power supply could be meaningless. A short in the harness would pull the voltage down to a level below what the PCM needs to stay online, even if the power supply was external. Especially when you consider than many of the power feeds inside the PCM are shared circuits. Something pulling down voltage on the intake runner actuator circuit could easily shut down other systems, or even the PCM itself.
Just an afterthought, but the ASD relay powers both the PCM and the short runner actuator:
View attachment 570024
It's worth a few minutes of time to swap the ASD relay out and try it. I remember another member a year or so back who did a cam/swap and had similar symptoms to what you are having. He ended up finding that his ASD relay had a bad (high resistance) connection on the contactor. When It started drawing current, the voltage dropped to a level that was shutting down the PCM. When he replaced the ASD relay, everything started working again.
I'll look and see if i can find the thread.
Edit: It was this thread:
Yes, I can connect to Engine computer with Alpha. I can connect to Body Computer with alpha and do all kinds of stuff. I can connect to the RF Hub and I even programmed a key that will lock/Unlock the doors. I can retrieve the 4 digit PIN. I can poll the computer and get all kinds of information...
www.ramforum.com