Ford Ranger / B-Series :: 1988 - Won't Idle - Starts Right Away Then Die?

88 ranger. 2.9L manual. Just bought this truck. It ran great when I bought it. After a day or 2 it would idle rough. Almost die but it wouldn't. No check engine light. It seemed to do this intermittently. Some times I'd start it and it be fine. Other times I'd start it and I'd expect it to die at each stop light.

Now for the last couple days it dies on every start up. It won't idle. It'll start right away and then die. I can keep it going by keeping the engine rev'd but the check engine light is one. If I keep it running and start driving down the road it'll drive with the check engine light on for about 5 minutes. Then the light goes out and it runs like normal, even at idle, until I shut it off. Then it's the same story at next start whether it's right after I shut it off or hours later.

It doesn't seem to matter whether the engine is hot or cold. When the check engine light is out, it runs great the rest of the time whether at speed or at idle. To me it sounds like a sensor is on it way out. I figure if it was vacuum, it happen at every idle, and if it was fuel it happen all the time or at least every idle. Tried to get a code at parts store but the reader wouldn't work. It couldn't tell it was plugged in the the truck for some reason.