Toyota Repair: 95 toyota lite ace

Question
My Lite Ace has a 5k motor with dual air con

I notice on the throttle linkage where you would adjust the idle there is like a vacuum operated idle module.  Mine seems not to be working.

I can not get my van to idle high enough to put the air con on.  It stalls.  Even without air con it stalls when I come to a stop.  The idle set screw is all the way in and does not reach anything.

If this unit is vacuum operated then maybe I have a vacuum leak.  But I think the bugger is defective.

Please give me some advice.

I am also trying to follow my vacuum system on the engine. If you can point me to a good web site info I would like to chase the system to look for leaks.

There is a hose missing from the valve cover to the air filter.  I will get that done today.  I think the last mechanic just left it off.   Philippines is not the best for getting repairs done.

Thank you in advance
Tim Lorenz

Answer
That vacuum unit is designed to hold the throttle plate open a little after the engine is shut off and there is no vacuum, as soon as the engine is running vacuum is applied and the diaphragm is pulled back, that's all it does. The throttle stop adjustment is factory set and should never be adjusted. There is another problem, vacuum leak, hose disconnected or engine misfire? Reinstall the disconnected hose and try to locate any other vacuum leaks. Try spraying the suspected leak areas with some brake cleaner in a can, if there is a leak the engine will race up.