I have a 2000 Pontiac Grand PrixSE 3.1L 4T65E Transmissionthat after approx 10 minutes (give or take a few minutes either way) just shuts down as if someone turned the key off, except it's still in the run position and the lights in the dash come on. I'm at wits' end with this thing and am done putting any more of my time or money into her (I don't think there's much else left to replace.

No DTC's found
Replaced Crank Position sensor (both of them), Camposition sensor, Both O2 sensors, MAF sensor, MAP sensor,Ignition module, and the list goes on.

Can any part of the PK3 security system cause this or is the security only used at startup? Hypothetically, if the key was able to be pulled out of the ignition while driving (left in the run position of course) would it have any affect on anything?