IAC Motor?

Hi,

do IAC motors fail often? I have a 93 euro 95K 3.1L

What I see, is after the car is warmed up, and ONLY at idle, the tach will "flick bounce" down from 900 RPM, or? and then quickly recover. The engine never stalls, but you can hear it when you see it...

It's been doing this for a while now, and hasn't gotten any worse, but I'd like to get it fixed... (makes me nervous)

Any ideas?

If the idle drops suddenly, and recovers suddenly, it's probably ignition or fuel (injector drive signal) related, not the IAC. The IAC doesn't move that quickly.

could it be a failing crank sensor? I have replaced plugs/wires, ign module, and new fuel pump and fuel filter too...

any ideas?