Follow Up: Problem All Solved
You may be interested to hear the ending of my battle with an uncooperative engine idle.
Yes, the replacement of the Throttle Position Sensor solved the "up and down" aspect of the idle problem. But the engine continued to idle rough, especially when cold. Along came help from Tech 444 on justanswer.com, who suggested that the EGR ports in the intake manifold could clogged up with carbon and sent a service bulletin with repair instructions. Yes, that procedure helped, but not totally.
Well, I continued to read my trusty Haynes manual about the EVAP system (the canister setup for catching raw gasoline vapors) and went ahead and tested it -- which also proved to be defective. Sure enough, after repairing the unit, the darn rough idle FINALLY CAME TO A HALT.
The bottom line of my experiences is this -- THREE systems had been at fault: the TPS, the EGR, and the EVAP. 
So keep plugging away fellow rough idle mechanics -- especially if you own a 1990-1993 Accord known to be trouble prone in this regard. 
(I am a witness here that it does not always pay to buy a "great used car with low miles" from a nice church-going old lady, etc, etc.) 
Last edited by gulfview; Nov 6, 2006 at 04:48 PM.
Reason: Clarity