It sounds to me like alternator issues - I've experience very similar symptoms with my '92 EX (also D16Z6) but they aren't as quite as bad.

I'm not sure how much voltage the alt on our cars is supposed to put out at idle (when warm) so I can't say for sure how much you should "notice" the alternator when you put more electrical strain on it.
However, you shouldn't notice a big difference in idle depending on the fan speed.

On mine I can hold the brake and in most cases the idle will drop a little and when I let off it will return to normal. If I pump it, as you did, the rpms will spike just a little and then return.

I've found that if I remove most of my taillight bulbs w/ 2 remaining I don't get a dip in rpms when I hold the brake but, if I remember correctly, I can still get the spike by pumping the pedal which I'm assuming is due to the ABS pump :hsdunno:

Anyway, it's possible that the bearings are bad/going bad on both of our alternators or maybe they simply need a rebuild so they are putting out the proper voltage and so dont have to work as hard to keep the engine running and battery charged. I don't know enough to say for sure.

On my car I can tell whether the alt is really working or not while shifting because the revs drop a lot faster when it is.
My car also has that high-pitched whine sometimes and I know it's the alt because when I drove the car on a 1/2 dead battery the sound was super loud and non-stop. Plus the car drove like crap and the revs dropped super fast when shifting, even worse than what I'm used to with the A/C on.


I got a rebuilt Denso for $160 total and would have installed it already but it arrived late and now due to my schedule/weather (oh and I'm lazy) I've yet to get around to it.

I hope this helps, I'm no mechanic and I can't say for sure that you have the same problem as I do but I am 100% convinced that my problem is the alternator (I wouldn't have paid $160 if I had doubts) and you seem to have similar symptoms.