Well, I installed a new RPM sensor, Cap and Rotor. (Along with O2 sensor, Air filter, New plugs, New Fuel filter that had been done in recent months) Checked for vacuum leaks around injectors. Inpected and checked all the elbows. Removed and checked the vacuum tree. Replaced one vacuum line that was as hard as a rock. Cleaned the IAC valve which was very clean to start with. Still I have a miss at Idle. I checked the actual vacuum at idle and found that the car is pulling 18-20 inches of vacuum. I do not know if this is normal. When I rev the motor, it draws 25-27 inches. GAs milage is 20 city and 28-30 highway so I think it is safe to say the car is running fairly well.

I am thinking that I am down to 3 items. Fuel pressure regulator, Fuel pump, or IAC valve. Any additional thoughts before I start driopping down $400 plus to purchase these parts in order.

You might check out the spark plug wires, preferably when it is dark outside. With the engine running and plug-wire cover removed you may be able to see arcing from the wires (little blue sparks), makes for a nice little light show and conversely poor performance.

Have you tried the wires? My 98 needed new wires. It ran rough on cold starts in cooler weather and would randomly miss at idle when warm. New wires made it smooth as new.

I would love to see you figure this out,
I too have done all you have done with the same results

I have not clean the fuel injectors yet.

good luck,