1985 Ford Tempo

Hi Everyone,
I am a newbie here, glad i found this forum. I have a few questions. My idle is high when first start the car and it stays that way until i drive for a 1/2 mile. I think the car runs a bit high when i am driving it also, but i do notice when i park the idle is high for about a minute or so. The idle speed control motor has been replaced and so has the throttle position sensor, any other suggestions? I also would like to know what are the signs of the egr valve or sensor going bad.
Thanks

you may have to clean carbon build up out of iac it also builds up in egr clean with carb cleaner