99 7.3 wont start
 

Ok this is the third time this has happened to me. After I installed a php chip in my truck sometimes you go to start it and it will not even crank. If I let it sit and come back hours later it will start fine. It just happened for the third time and I have not went to restart it yet. I plugged my old dp tuner back into and the switch doesnt light up so its not getting power. I think the rubber piece that holds the pcm in the firewall popped out when I tried to pull the pcm last time because i couldnt get it out. If it restarts when I get it home then I am going to pull the pcm and put it all back into place. Any ideas? Is the pcm just loosing power and takes time to reset or what could be causing this? Thanks in advance