I have a 2000 K3500 7.4L crewcab short bed. The problem is that sometimes it won't start. It will fire but then die right away. When it happens you can't hear the fuel pump come on. You try to start it a few times, then let it sit and it will start up. I've been told that it thinks it's being stolen and is shutting down. I've taken it to the dealer but they can't find the problem. They say to bring it in the next time it happens. But by the time they come get it and get it back it starts. Any idea?