2000 Grand Am GT erratic idle when warm Help?

So idle starts jumping from 500 to around 1000 rpm or so back and forth. This only happens once the engine is warm and only when it is in park or neutral (not in drive).
Check engine light is on. It drives fine otherwise. Changed the idle air control valve and the MAF. Couldn't find any vacuum leaks. Bled the cooling system a few times to make sure air is not in there. no bubbles.
Two interesting things i found stop the oscillating idle:

1 - When i unplug the idle air control valve before i turn the car on it doesnt do it. Thats why i replaced it (but nothing changed )

2 - when i unplug the vaccuum tube that goes to the crankcase from the air intake duct. (I changed the PCV and also nothing)

Any ideas guys,
Please help