westside

So I have a 1995 1500 suburban that is having a rough idle and is hesitating when I go to gas. Problem started one day I was at a red light, acted as if wanted to die out. So I gave it some gas while in neutral and it didn't die. Once the light turned green I gave it gas and it hesitated pretty bad and then started going fine. I pulled over to try and see what was wrong but couldn't see anything wrong. Then proceeded home and was thinking maybe I needed a tune up. Gave it a full tune up, cap & rotor, wires, plugs, filter, oil change and it continued. I then let her sit for about a month and now she won't stay running. I tried to google some problems to see if anyone has had similar problems. People have had similar problems and they stated that they've tried numerous of things and still had the problem. I've recently tried changing the TPS sensor, EGR vale and MAP sensor and no difference, still dies out, still hesitates when given some gas. has anyone had similar problems? What have you tried? Did it work? Any ideas on what I'm missing? Thanks in advance for any advice.