Problem with 89 Olds quad 4, d code engine.?

On this quad four engine I have a problem with the idle wanting to flood out after sitting for a bit. I have changed the MAP sensor, O2 sensor, the TPS, fuel pump, fuel filter, timing chain and sprokets, plugs, boots, air filter, etc, etc. I have not changed the idle control modual as the car sometimes will idle like new, expecially when cool. It is a very frustrating situation that I could use some help with. The #2 plug appears to be running richer then the rest, could it possiblity be a bad injector?