My idle sounds like a huge vac leak... bounces to 1500, then almost dies (i mean super close)... I was just messing around looking for leaks and I took this hose off... my idle immediately became steady at 900 or so. I followed the hose and it connected to the bottom left soleniod on the rack... My problem is I don't know what that solenoid does or if it is actually working properly. any other ideas??

 

Go to the 2nd gen FAqs and click the link to a '89+ service manual.
Read (if I remember corrfectly) the sections about emissions.
You will learn what this solenoid is for and how to test it.
You can do the testing yourself.
Good luck.