why does my 1995 Isuzu truck 2.3 engine crank up run good then just die

What is your question?

I put a new head gasget on my 1995 Isuzu truck 2.3 put it all back together it cranks runs great for 3 or 4 seconds then just dies. it ran great before replacing the head gasget, just ran hot, now it wont stay running