My 2000 Blazer fires up right away but dies right away too. I keep trying it but nothing. Then I come out later and it starts right away and runs fine.It has been doing this for a few days now. It is really cold out (-20 c). I got it going the other day and while driving it the security light cam on but still ran great. It did it a long time ago before but then I had no problems. Hope somebody has an idea. Thanks