2001 Dodge Intrepid 2001 dodge intrepid p/s noise

I have a 2001 intrepid with a 2.7 liter motor.When the car has sat overnite and i start it up the power steering makes a high whinning noise,then goes away after about 10 secs or so.I have replaced the idler pully,and p/s pump with a used one.It doesnt whine as long but problem is still there.Could it be bad p/s fluid?.Help""""lol