I've got vacuum problems with my 2.8 & have replaced all the hoses & connectors I can find. I've located the hoses that go to:
-thermal switch in the air cleaner shroud
-air injector (smog) pump
-cruise control actuator

I've still got a really unstable idle. I know a hose goes to the HVAC system - I found the vacuum switch on the drivers side of the ventilation unit. There's no vacuum present there. I traced the vac line up behind the dash, all the way over to some sort of switch which I can't see. I couldn't find where the vacuum line feeds through the firewall. Anybody know where that's at?

-bump- (that's right, I'm not too proud to bump myself <img src="/forums/images/graemlins/smile.gif" alt="" />)

there should be a vacuum diagram under the hood somewhere.

uhh.. you mean the vacuum hose between the two A/C hoses? <img src="/forums/images/graemlins/kewl.gif" alt="" />

if you have a rough idle it could be other things as well. check for leaks before you start tearing things apart. check your egr valve as well.

Hmmm - do you mean the 2 A/C hoses where they meet the firewall? "Cause there's nothing there but a little white plastic connector of some kind <img src="/forums/images/graemlins/confused.gif" alt="" /> (it's dark & raining out so I can't get a good look at it right now....)

Pictures :

The vacuum hose goes between the a/c hoses. I've conveniently removed those hoses to get a better picture for you <img src="/forums/images/graemlins/pfft.gif" alt="" />



That connects to the vacuum splitter thing at the rear of your TBI - the same splitter will have a couple other hoses coming off it.

Wow, dude thanks for the awesome pictures. Almost makes it too easy! It looks like my hose is also disconnected - which explains a lot.

I'll have to slap some hose on there tonight and see what happens...

Well, adding that hose did the trick to get my defogger working. Thanks for the help.

I'm still working on my stalling/rough idle problem. I'd thought it was related to the vacuum or PCV/EGR. By now I've replaced all the vac. tubing, and both the PCV valve & EGR valve. Any other tips as to what could be the cause? Maybe the vacuum control valve (I think it's located next to the EGR & Distributor?)

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="" />