at least VISUALly INSPECT the control unit..
They never get looked at ..I've seen corrosion at the electrical plug..
I suspect yours is just bad though.
They do that.

remember ..
never look first ...always ask online first.  lol.

On 10/16/2014 6:44 AM, Stuart MacMillan wrote:
> Just got my son's "new" '87, and we were told by the seller it had an idle
> problem.  He's driven it about 200 miles with nothing more than a bit of an
> idle surge once in a while, but now it won't idle at all cold, and when it
> warms up for a couple of minutes it races up to 3000 rpm and stays there.
> Restarting doesn't help, and only when I unplug the idle control valve will
> it stop (die).
>
>
>
> I've checked the TPS with an ohm meter and it works fine, and the idle valve
> hums.  I can't find any vacuum leaks (propane torch probe), and it was
> recently tuned up.  So, is it possible for a bad Idle control unit to cause
> this?  It seems odd that an engine can run at 3000 with the throttle closed!
>
>
>
>
> The only way to test it is to replace it for $200.
>
>
>
> Thanks!
>
>
>
> Stuart
>