Prepare for sticker shock on the EHA. Occasionally you see one for sale on eBay or other places, but they are used and subject to being bad also.
Might try changng the o-rings first, who knows.
The idle control valve is on the passenger side of the fuel distributor. It sits by itself in a rubber sleeve/holder. Has two rubber hoses about 3/4 inch diameter going to it. Looks kinda like a juice can. Don't know best way to clean it, but I used spray carb cleaner, the followed up with light oil.
The hoses on the IAC can harden and leak, definitely causing idle problems. They are pretty difficult to replace without removing the whole fuel distributor. We've done it, but it takes patience and dexterity.

DG