1998 Chevy Astro Engine starts then stalls after 1 second

I have the exact same sounding problem with my 2000 Astro. After replacing the fuel pump, spider assembly, ECU and other things, it turns out it is something with the security system ( Passlock ). It will start for a second and then quits. The security light on the dash is on. Sometime it will start and run just fine for a week or so, then starts this problem again. Has been towed 4 times to the shop, but they still can't find why. It is at a Chevy dealer right now being work on again. If I find out something for sure this time, I'll advise it here. Otherwise. Anyone want to by a 2000 Chevy Astro?

Took my 2000 Astro to my local chevy dealer where I bought it. They replaced some sensors and said the problem was fixed. Drove from Milwaukee to Central Florida with no problems. Then while in Florida it won't start again. I had it towed to a Florida Chevy shop, and the guy takes one look at it and says it is my ignition switch causing the PassLock to engage. Well it has been a couple years now, and it has never happened again.