was that hose you replaced, previously plugged off (like in my pictures)? or was it wide open sucking in air?

If it was wide open, try plugging it off properly (just for testing purposes, you'll lose defroster again) and see if your idle improves. If your idle improves, you have a vacuum leak under your dash you should fix if you plan to use vacuum to operate your defroster valve.

I chose to use a much more relaible piece of technology known as a "spring" to operate the air vent valves, and thus capped off the vacuum port seen in the above pictures <img src="/forums/images/graemlins/kewl.gif" alt="" />