recently my 94 suburban with a 350 has had issues staying running. when cold it will start right up and idle on it own for about 3 min before it starts to surge 800rpm up to around 1500 for a minute then sputter a bit then die and wont restart unless i use starting fluid or till it sits for awhile then it will fire right up again. but it stays running as long as i hold the idle up or rev it with no hiccups. i thought about fuel pump but i would think it just wouldn't start and would not rev without hickups. this is my DD so quick help/response would be much appreciated

 

well I'm not so quick but suspect a vacuum leak... a big one