So im driving a 1994 cheyenne 4.3 vortec. It has a little over 200 thousand miles on it. Tbi. When i start it up it runs good for a minute or two. But it has started to try to die after these two mins. If it is sitting at idle then it will die. After it warms up it drives fine and idles great. Ive completed a tune up. Have replaced my iac sensor, pcv , and im still having issues. Any ideas would be great thanks