The idler pulley that attaches to the alternator foot goes bad every 5,000 miles on my 2003 GT. The bearings are fine. The plastic around them goes away. Nothing is binding. I am having no problems with the belt and getting all of my boost. Everything looks good by eye, I will check it with a straight edge, but if I need to shim something, where do you start. It looks like if I add something it will just make it out somewhere else.
Thanks
Scott