Immobilizer Issue, Helo:(
 

Okay, so I finished the engine swap in my 04 GT a few months ago, and besides cracking a radiator, all has gone well. Now, last night I backed into my parking spot and left it idle for a minute or so while I closed all the windows/sunroof. Right as the sunroof was closing the car just shut off, all the dash lights/cluster warning lights are still on, but the car will not even try to crank. The security indicator light flashes very rapidly as well, all the fuses are fine, even the giant 120 amp one on the side of the box. Last night I left the car to sit over night with the battery disconnected, and still no dice. If anyone can shed any light on this, it'd be much appreciated. I'm aware of the potential issue with the immobilizer, as I did search, I just want to see if this is actually it.
Thanks

check your grounds and battery connections

Battery Terminals and Battery are both new, grounds are fine, just went over them again this morning. The only thing I keep coming back to is friend PCM, especially since there appears to be no power going to the OBDII Port.

I know, it was a cople of years ago, so what had happened to your car?)