hi i'm new to this board. my name is peter. i wished i joined the board sooner. back to the topic at hand... well my '97 discovery se is not running at this moment. it starts up good but then it dies after the car warms up. if i don't keep the idle up it just shuts off. and then after it shuts off, if i wait 5-10 minutes, i can start it up again... but it just dies again. can anybody tell me what this is. i just spent $250 on an alternator for nothing

please let me know what this is if this has happened to you
thanks
pete