First thing you need to do is get a good manual and replace all of the vaccum lines with new ones so you know that they are in good shape. Do one at a time so they don't get mixed up. Then you need to start troubleshooting the FI system. There are alot of things that help or hurt the idle control. A good write up I found a while ago is this one.I think I saved it from the other forum. Hope that doesn't cause any issues.
http://fm.no-ip.com/gslseidle.html