HI, im having problems with my idle. I know that your tired of answering these questions but i need help bad..

Ok
1) Engine idles at 2000-2250 (curb idle. Hot or cold)
2) Replaced the IAC Valve and still have problem.
3) If i rev the engine up it revs down very very slow.. I can rev it to 3000 and it goes down very very slow..Too slow..

Is it the PCV valve or could my Throttle return spring be bad?

Cant find any vaccum leaks or anything. Can someone please help me.. Im not sure what to do next. I have a 88 v6 2.8L. CAN I ADJUST MY IDLE SPEED OR WILL THAT MESS IT UP???/
PLEASE HELP