Update. I think I've got it finally. Pulled throttle body and IAC off and took apart. Cleaned everything up real good a did freezer test on IAC. Didn't move at first. So took it out to garage, soaked it really good and tested again. This time she opened up like she was supposed to! Idle is great now!!

Now, what is this part in the pic? The solenoid with the plug and the vacuum lines going to it? I saw it on this forum once before from another poster, but not sure where. When I'm driving now, that thing is clicking like crazy and driving me nuts!! It has never made a noise before til today. Gotta figure out why and how you stop it. Any help is much appreciated!

 

That's great news!

That seems to be on the passenger side of the engine. Looking at diagrams I guess it is either the PRC Solenoid Valve or the EGR Boost Sensor Solenoid Valve.

In any case, follow the vacuum lines to see were they connect to and match it up with the diagram under your hood. Inspect for leaks/ brittle ends or just go ahead and buy 15' of vacuum hose and replace them wholesale.

1997 Mazda 626 Diagram for Vacuum System: Engine Mechanical ...

 

I was thinking PRC solenoid at first, but after watching a Devon video last night, the PRC appears below it. Going by the schematic it's the purge solenoid valve. I've traced the lines and looked for broken pieces, all is good. One line runs from it to just below the throttle linkage. It just clicks alot. At idle, it only does it every so often, but if I'm driving it is get a steady clicking from it. Makes no sense why it all of the sudden started doing it.

 

Devon explains the purge system here:
I'd replace the solenoid and inspect all the lines.

 

Actually just watched that one and another one. I'll buy some new line in a bit just to have on hand. Just checked both lines and they don't appear to leak at all, but you never know. I might just unplug it for now if it keeps doing it. But man, idle is awesome now! Now more high idle or surging!!

 

***UPDATE***

Ive read numerous post on various forums where the original poster never posts back with any results and leads to a dead end for folks that are searching with similar issues, so ill post up my resolutions to the majority of my problems.

At first I had an issue where the car would start great in the mornings, but after driving, it would take awhile to start back up if I killed it for any length of time. It would also stumble and almost die after idling for a few minutes. Was just one random stumble, but rpms would go down to near zero, then it would pick back up and run fine for a few minutes, then do it again. Anyways, that issue ended up being my fuel pressure regulator. When it was hard to start, I would usually smell fuel. Finally pulled vacuum line off of regulator and fuel was just dripping out. So I replaced that and those issues are fixed!!

Next was my odd idling either when warm or cold. It could be totally up to operating temp, and idled down to normal rpms, but as soon as I would put any sort of load on the engine, the rpms would jump up to around 1500+, and stay there for quite a while, as in several minutes. This was totally random as well. Sometimes it ran perfect, sometimes it didnt. I tested the resistance of my IAC motor, and it tested fine. Tinkered with a few things here and there, til I finally pulled throttle body and IAC completely off. Did the freezer test on the IAC and it failed the first time. The spring and rod did not move at all. So I took some cleaner, I think it was a seafoam spray, and soaked that whole area of the IAC. Let it sit for quite some time, then drained off the seafoam and blew it out with some air. Stuck it back in the freezer and bam, hit it with the hair dryer and it started opening up!! Glad I didnt have to spend that 400.00!!

Next issue that started after that fix was the annoying clicking of the purge solenoid valve. Not sure what happened with it, or why it even started clicking. It didnt do it at idle, only did it if it was under a load driving. Put it up in the air on jack stands, put it in gear and revved it up a bit. Thats actually how I found out what was making the noise. With that I re-checked the vacuum lines running to it, but they were all in place and free of leaks. So I unplugged the sucker, loaded up the family and went to town to do some Christmas shopping. Of course the CEL came on about 15 miles into the trip. After it came on, I plugged it back in, hooked up my scanner and cleared the code. I know this is no fix by any means, but it hasnt clicked since doing that.

I am still getting odd downstream O2 sensor readings and getting a P0420 catalytic efficiency code, but until I can afford a new cat, ill have to deal with that. Im sure that is caused by all the excess fuel that was being dumped into the engine from the bad pressure regulator. I guess it toasted my cat. Ill replace it in a few months and go from there.

Anyways, this is just an update on what my engine was doing and the steps I took to fix my issues. No, these wont fix everyones who has the same issue, but maybe it will help a few others down the road.

I greatly appreciate all of the help, suggestions, and advice that was given. I hope in turn I can help someone else in the future. Now onto my next issues that ill post in a new thread!!!