i have a 2000 xtreme that starts but dies instantly i can keep it running with my foot on the gas after about 1 minute it idles fin it has plenty of power runs great other than this it only happens 35% of the time other times it start fine

go to autozone, ill put money that your alt either going bad, or maby a bad connection from it, but either way it has drained your battery down to next to nothing and now this is where you are

i don"T think its battery related the truck cranks with no problem

check your idle control motor. it might be clogged with carbon or not working at all. have the computer scanned to see if there are any codes in memory.