Cranked car to warm up , put in neutral and come back 3 to 5 min later and it was dead and now wont start!

Hello, The ignition switch portion doesn't worry me too much, but you should certainly inspect by backprobing the connector to ensure it is functioning as it should. You say it was dead, do you mean it shut off, or the battery died completely? If it drained completely, test the battery. You may not be getting enough voltage to run the powertrain control module. You will want to start with the basics - scanning for codes, making sure there is actually gas in the tank, try to start it with the throttle open just a little, try starting fluid in the throttle body, check fuses and relays, test the coil, etc.. Running through those, something should give you an indication of what is going on.