91 4Runner Throttle Body/Intake "Idle valve?"

My truck (4 cyl., EFI, auto trans) just developed a huge vacuum leak. I checked under the hood and isolated the problem. It's missing part of the throttlebody assembly. I think it's an idle adjustment screw of some sort--not sure of the proper part name. I covered the hole with duct tape and that works fine, but I want to fix it properly.

Any suggestions or scematics/pictures would be appreciated--I could find these at the dealer or even at about 12 different salvage yards.

The opening is on the right side of the vehicle and near the mouth of the throttlebody where the air intake hose attaches. It is oriented vertically and appears to have internal threads. I can't see any hoses or electrical contacts that would be connected to whatever it is that fits inside the port so I am thinking it might just be a screw and spring type of device (needle valve?).

Any help would be appreciated.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/engine/34throttle.pdf

Thanks for the link. I still can't make out what the missing piece would look like. I've circled the area and posted the picture:
http://www.aoloa.com/images/throttle.TIF
Is it just a cap? There are threads inside and I think this is the idle adjust valve.

Can you post a link to the idle adjustment information (Page MA-11)? I cut and pasted the section that refers to the idle speed adjustment below:

3. (M/T)
INSPECT DASH POT (DP)
A. Warm up engine
Allow the engine to warm up to normal operating
temperature.
B. Check idle speed and adjust if necessary
(See page MA–11 http://personal.utulsa.edu/93rmsour/1993/93truckr/ma/maint.pdf)
Idle speed: 750 rpm

Thanks.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/maintenance/2maint.pdf

Here's a link to the entire manual:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

It is in the sticky post at the top of this forum.

Brian,

Thanks for the links, most timely!

JRF

http://personal.utulsa.edu/~nathan-buchanan/93fsm/maintenance/2maint.pdf

Here's a link to the entire manual:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

It is in the sticky post at the top of this forum.

You're welcome