I've done a bit of searching and I can't find anyone with my exact problem. I have a 99 2 door with 4wd. Sometimes.. only sometimes my security light will come on,and the blazer will be about to start, the. doesn't. Then all I have to do is turn the key off, wait about 5 seconds and it starts right up. I don't think there is any aftermarket security system.

 

I have the same problem in my '01 ZR2. It seems to only happen when i put the key in and quickly turn it to start it, it would crank but not start. If i put the key in then turned it to ON and wait a few seconds, then start it, it stats right up. I don't know for sure why this happens but i read somewhere that you may have to reset the security system.

 

Mine does the same thing! I'll look into it a little more. I'll update this for you if I find a fix .