The O'Reilly distributor you mention, did it happen to be a re-branded rebuilt? It wouldn't be the first one I've heard has been bad out of the box. Since the PIP doesn't act up unless hot and tests just fine, the rebuilder changes a few bushings, cleans it up, slaps a new cap & rotor on it along with their sticker, and puts it on sale. Just waiting to piss-off the next guy who winds up with it. You're best off replacing the PIP yourself with a decent quality new part, it's not hard to do for someone mechanically inclined.
The next time it acts up, check the fuel pressure at that exact moment to make sure it's within range (about 32psi at idle, 39psi with the vacuum line disconnected from the regulator). The nose-dive at wide-open-throttle often indicates a fueling problem - your foot and the throttle body give it more air, but the injectors don't keep up with the fuel it then needs.
Also check if you have spark. If you don't have spark, it's very possible the PIP again and I'd toss the distributor back at O'Reilly for replacement #2. You could also throw a bag of ice on the distributor to cool it off faster and see if it starts sooner.
On a 25 year old car it could be lots of electrical gremlins or corroded wires that heat up and lose connection but the most common in our cars remain the TFI and PIP.
