05 gto killing me.

Hi, I have a 05 GTO in the shop. After flashing the pcm I have a issue with intermittent no start. When it does not start the check engine light will stay on when the key is turned off. The key has to be removed from the ignition then after about 30 seconds it will go out. The theft system light will remain flashing as well. I have relinked the bcm to pim and pcm to pim. i have done a theft relearn as well. All of these using a tech2.
After several key on key off cycles it will eventually start as long as you get it at a time when the check engine light did not remain off during power down(key Off). it is not setting any codes. Oh yeah, replaced pcm, pim, and bcm still have same problem. Thanks.

It's not a key fault is it? Or maybe the earth wire behind the contact ring around the ignition switch?

New key fob. I wasn't aware there was a contact ring. I will remove cover and check it in the morning. thanks.

Hope that works out. Would tuning off VATS help a little? I know it's not made for these situations but I've cheated with it before. Also, I find that diagnosing whatever fault code you find in the BCM or other modules step by steps sometimes helps get to the root of the issue. If you need help with GMSI, let me know. I can post you code descriptions and flow charts.