The only thing I do not remember reading about in your post was the ASD(Automatic Shutdown Relay). The ground circuit for it is also controlled by the PCM. I think more than likely you are on the right track getting the PCM checked/or repaired.

Good for you! Where are you going to send it to get it tested? Let me know if you need me to post a link to SIA electronics for you. If you do send it to them, they ask you to write a written description of symptoms and everything you had done in an attempt to correct it. This helps them pinpoint the problem area. Make sure you include your Vin number and mileage. There should be a form you can print out on their website. I can tell you that SIA will actually repair your PCM instead of just sending you another that might have come out of a junkyard.

Let me know if you need any more information.

Jason