other places for vacuum leaks would be around PCV valve or at the valve cover gasket for example
reading your original list of items replaced I doubt you left anything like this behind, but if not: worth replacing any leaking gaskets
ah… and replace PCV valve if you did not do it yet: I’ve seen a couple of cases where it rattled, but did not work well, after replacement car was working better, besides it is only few bucks to replace
It will be interesting to see what the problem turns out to be. Keep us informed OP.
A vacuum gauge is the quickest and cheapest method of determining whether or not there is a vacuum leak.
The problem with buying a a length of hose and replacing and praying is that the leak can be in an obscure place. By that, I mean inside the dashboard. There are various vacuum pods that control heat and defrost functions, etc.
Those pods have rubber diaphragms and there’s a wad of a vacuum hose inside the dash also.
Wow. I didn’t think of that ! Thanks for the heads up.
Collective intelligence wins 
Vacuum line by the foot is dirt cheap. If you have any suspicion whatsoever that it might be the cause, you may want to just replace it. I’d do it one line at a time to eliminate the possibility of crossing the lines.
IMHO the same applies to rotors and distributor caps… and spark plug wires. They’re inexpensive enough to just go ahead and replace them.
Wow where are you ordering this stuff from.
Reminds me of a BMW that the shop that ordered the new head waited 2 weeks for the new head to come in.
Yosemite
LoL. It is a 25 year old vehicle. A number of parts are discontinued and I have OCD when it comes to electronic parts … they have to be Denso and in great condition from reputable sources at the right price. It takes time to find the right ones. By the time they ship them and go through the mailing system …
Re vacuum leaks
All the vacuum operated systems, the source of the vacuum comes from one place, the intake manifold. None of those gadgets which connect to the intake manifold should leak, b/c that would allow unmetered air into the intake manifold. That’s what you want to test for when checking for vacuum leaks, that none of the gadgets or their hoses is leaking. IMO the easiest way is a hand-held vacuum pump. All you have to do is find where the vacuum from the intake manifold is sourced, and connect the vacuum pump to it instead of the intake manifold, then pump it up to see if it holds vacuum to 20 mmHg or not. Sometimes you have to break the vacuum tree into 2 or 3 separate limbs, and test each one separately, but its the same idea. Plus you can use the gauge on the vacuum pump as a simple vacuum gauge too for checking the intake manifold vacuum with the engine running. Getting a baseline measurement on what the intake manifold vacuum should be at idle when the engine is running well is good info to have. Mitty Vac I think is the name for the most commonly available brand. Not overly expensive test gadget and a must-have if you are a serious auto-repair diy’er.
UPDATE:
The problem was a combination of distributor cap and igniter.
-When the igniter was replaced the vehicle started running even smoother than before and it was able to recover fast from the poor start condition … but the symptom was still there just diminished and compensated.
-The distributor cap was inspected and upon cleaning of the contacts there were carbon deposits that would scale off. One of the pins had 0.5mm deposit on it making its air gap out of spec (basically 1/3 of the pin was gone). The entire distributor was replaced to remove any chance the coil electronics were degraded too (this was a 25year old distributor coil with a 5 year old cap).
(the intake air temp sensor was also replaced, completing the entire sensor series, restoring the engine characteristics to within 99% of it’s original manufacture)
Thanks to everyone here that contributed with your suggestions ! ! !
Thank you for letting us know how you got it resolved! And good luck going forward.