Your 1990 Lumina Euro will turn over but not start right away on cold winter mornings but if you let it sit and try a few minutes later it starts - could this be the fuel pump slowly going out?
Next time, try this: Turn the key on for a couple seconds WITHOUT TRYING TO START THE ENGINE, then turn it off, then try to start it. Sometimes the fuel pressure leaks down overnight and it doesn't build up immediately when you try to start it. If it runs ok the rest of the time it might just be a slow leak in the fuel pressure regulator. If that's all it is, it won't affect the normal operation of the engine unless it gets a lot worse.