1999 Mazda Protege idle speed changes, occasionally stalls

Get a can of spray gumout, start the car and spray around, pay attention to vacuum lines and manifold, if the idle changes, you found a leak. You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!

The other possibilty is the idle air control, it,s bolted to the side of the throttle body...

I think you are right about the IAC and vacuum leaks. I need to get a garage heater first though, to check this out more fully.
Can I clean the IAC, since I priced the part and it costs $350.00. Or is there any way of double checking that this is the cause, other than ruling out the other black rubber hoses leaking vacuum?

Ouch! yes I just priced it...WOW, the one on my lincoln doesnt cost that much! I would definatley reove the old one and clean the port out as a trial, but when there gone...there gone. Try finding the vac leak and plugging it. Here's a picture of the little bugger!