Those 1st generation IACs are not available anymore "new'.  I was concerned mine was going and called around looking for one and finally Jerry at 22re performance told me they aren't available. Mine ended up being ok and just some bad wiring.

During my researching of this issue I found that there is a way to update the Intake plenum/throttle body to the later model TB that doesn't use that early IAC (or not at all cant' remember).

Here is one of the posts I bookmarked and should start you in the right direction.

http://www.pirate4x4.com/forum/toyota-truck-4runner/642512-22re-early-late-intake-swap.html

 I had good luck with hard to find parts from yotayard in Colorado. Maybe reach out to them if either way.. for an IAC or if you decide to swap.

http://www.yotayard.com/home.htm