Well, many, many have queried and prescribed regarding this.  My 2.1
idled way too fast, sometimes.  A good mechanic said (as have many of
you) idle control valve (he called it idle air controller, but it was
the same beast).  I left the van with him, asking him to do all usual
"tune-up" things like plugs, wires, rotor, distributor cap as well.  He
did those, but only cleaned the icv, telling me that a new one cost
$550, that there were only two available in the U.S., and it would take
him several days to get one.  I found one on-line at United Auto Parts
for $222.  Has anyone had any experience with them?  Are their parts any
good? I haven't ordered it yet.  He did not mention the idle control
unit.  I found that it costs another $280 or so.  I drove the van 30
miles, all seemed well.  But after reading all the past posts, I thought
I'd set the idle myself, following instructions several have given.

I found two significant things as I attempted to do so:  (1) The
electronic unit on the end of the icv is very difficult to remove, and I
was afraid I'd break it.  How to remove it??  (2)  Looks like my
mechanic had simply turned the idle down to the lowest level the set
screw will go to.  At that position, my van is idling at about 1100 rpm.
That is, in fact, why I was going to set it myself.  But, it is as low
as it will go, and I cannot disconnet the icv anyway.

So -- do I need an icv, and an icu, one or the other or both?  The icv
does hum (or has a very slight vibration that I can feel).

Any help appreciated.

David McNeely