98 Silverado Fires Then Shuts Off!!

I have a 350 Vortec. I parked it outside of work went back outside 8 hours later after it rained and it wouldn't start. It will fire like it's gonna run then shuts right back off within 1 to 2 seconds. It's getting fuel to the injectors. It has always ran great and never acted up or idled rough. Any help is much appreciated!

Sounds like a problem I had on my '99 5.7. It would happen mainly on damp days. Turn your key on and watch for the instrument cluster lights to go off. I forget which ones go off first. If the security system light stays on, you narrowed it down. It drove me and the gm mechanic crazy. Even had the wrecker at the house to tow it in, tried the key just one more time and it fired right up like there was no problem. Finally started getting worse. The mechanic changed out a security system module which was located in back or under the radio area. It was a little bigger than a cassette tape box. Sorry for not much more detail, but it hasn't happened since the replacement about a year ago (knock on wood).

It's very strange, I went back today and started it, it died a few times, then the idle smoothed out and it's now running and starting perfect. I have had no "Check Engine" light. It's still cause for concern, but for now it's like it never happened. Thanks for your help.

i have a 99 tahoe doing the same thing, i took it to the mechanics and they told me it was the mass air flow sensor. they fixed that but it still doing the same thing, it fires up and then dies a immediately. any one who can help please do.

same on my 96 5.7 silverado, just got the truck this weekend and now wont this! im gonna try swapping that security module, can anyone tell me where to look?