Why is my idle air control going bad?

I have a 1998 Honda prelude and it's an awesome car I have no problems with it except for my idle air control sensor. It went bad but I had the same car for parts so I took it off there, for a month or so I had no problems, a few days ago it started idling funny again and today my check engine light came on and it idles bad. What could cause it to go bad?