Hunter.....update:

Removed the Throttle Body and cleaned. As the pic shows, the inner portion of the butterfly side was not very bad:




All cleaned:


I discovered that there are 2 lines on the bottom where coolant flows to (yellow tape on them in pic).
As you can see, those coolant lines flow to the same spot where the Idle Control Valve goes. Not sure how the coolant temp works to increase/decrease the air flow around the Idle Control Valve......and thoughts?
I was going to remove it to inspect/clean, but those 4 Phillips head screws were so tight I thought I would strip the heads out, so I left it alone. I did put a short hose on and blow thru it, and some coolant and then air came out with no problem.....so I guess its fine inside. Did spray some penetrating oil into the lines and then used the yellow tape to keep it in to soak good.





Top left-hand side of pic is the mounting area for the EGR.......ran some weedeater line thru both holes, and it was not clogged up.



So, I will be re-installing the throttle body, but dont think this cleaning will have any impact on the Idle problem (will not idle, but was stalling out). There is another solenoid way over on the other side, beside the battery. I think this one will open/close as commanded by the computer.......if this solenoid does not open, then there is no vacuum going to the EGR. Do you think this could be the issue? Guess I could remove this solenoid from my other Monty and swap out to see if it works.

Other suggestions?
Thanks

 

Great time to lube those throttle body cables, while they can be elevated so gravity can assist with the flow:

 

Check if you can activate the EGR valve with a hand vacuum pump. If EGR valve is stuck closed, it will have no effect on idle, just some reduction in fuel economy. If it is stuck OPEN - then no idle. I'm running out of ideas of what else can it be. If no improvement after all this, I'd be checking wire continuity and signaling from PCM to IAC.

I feel like this is a super dumb suggestion, but it is known to help with weird stuff - remove ground straps from engine and clean up all connection points (maybe do the same on the body too). Reinstall and hope it was a bad ground...

 

I forgot to mention that the EGR valve was in great condition......really did not need cleaning, but I cleaned out the small amount of carbon dust. I put a hose to it and checked that it worked, and held the vaccuum....was fine. Then put a bit of spray lube on the shaft that moves back/forth.

However, looks like that there is a solenoid beside the battery that turns the vacuum line on/off.....so, if that is failing, the EGR would get no vacuum.

I also hooked up the OBD2 scan tool to the port, turned the key "on", and let the scanner look for faults/errors. It came back saying that it was unable to access the information, and "go get technician". Also, there is no "check engine" light coming on.......seems that with a severe idle problem, there would be a "check engine" light displayed.??

Will check the grounds, but I think I they are in good shape. Guess I will put her back together, and try.......if still no idle, I will first try that EGR Solenoid beside the battery......just maybe.

 

Totally stumped here.

I just put back together the throttle body and components. Started up the engine, and once again, it will not Idle. It just drops down to 0 RPM and stalls out. Have to keep my foot on the pedal to make it stay running.

So I took the "EGR Solenoid" which is located beside the battery from another Monty and swapped it into the "problem child". (This isnt actually an "EGR Solenoid", but the vacuum line coming from it does run to the top of the Throttle Body). Cranked up the engine, and still did not want to Idle. After I forced it to run with my foot on the pedal, and let off, it did finally idle way too high......around 1200 rpm.

Any other ideas as to what the problem could be?

Note.....I also tried the OBD 2 scanner on the other good running Monty, and it gave the same signals....."unable to access data, call technician". So, must be that these 94s are OBD 1, or just not working with the scanner I have.

 

Unplug vacuum line going yo the EGR valve. If engine does not run (idle) you eliminate EGR as a suspect component.
Step 2, is like I mentioned before - time to start creacking on the wiring between PCM and IAC. Unfortunately, I can't help you with that, since I don't have diagram or specs for '94. If you have electrical schematics for it, post it here. Let's see what we can figure out.

 

Hunter......Will give that a try, unplug the EGR vacuum line and then start up and see if there is any difference. This will ensure that the EGR shaft does not move toward the EGR diaphram which opens up the air passage, which allows some exhaust gases to enter the intake manifold to be burned again. (I guess thats right?) I will plug the vacuum line to make sure it doesnt reduce needed vacuum elsewhere.

OK.....then I will dig thru the shop manual and see what kind of electrical diagrams I can find.
Thanks for keeping up with this thread, and giving great advice.

 

Bingo!!!
Capping the end of the vacuum tube is a good idea - the way you are not introducing a vacuum leak into the system

 

Hunter......Did the experiment. I pulled the vacuum line at the EGR and plugged the line with a big rubber plug. Cranked up the engine and the idle climbed to about 1250 RPM and held there constant. With engine running, I pulled the plug on the EGR vacuum line, and it made no change to the engine rpms......then I put the vacuum line back on the EGR, and still no change. Maybe the EGR does not even "kick in" until the engine is warmed up to a certain temp....??......not sure. But I did find the actual EGR Solenoid tucked away under the air filter box......what I had thought was the EGR solenoid over beside the battery was actually just the solenoid for the Evaporative Air System.

I tried to take some pics of the electrical configuration shown in the shop manual. The first couple pics are from Page 121, and the lines connect to Page 122, which I will then paste below:

Page 121:


Close up of the top of Pg 121:




This connects to Page 122:




Top of Pg 122, showing Idle Control Motor, and related components:




Does this help any?

 

Stepping back for a moment.........Is it possible that a fouled plug would create a misfire, and the computer would then make the engine idle faster to help compensate??? Just trying to step back and look for something simple as the cause of the fast idle.
So, at this point, I dont think its related to the EGR. Its not due to a dirty throttle body, as that is "spic n span" now.
It happened suddenly......ran perfect until that one day I started her up, and the idle just kept dropping to 0 and stalling out.
Hmmmmmm.......maybe a blown fuse (will have to see if there is a main fuse that covers the Idle Air motor and related parts.??????