Funky Idle - '87 5kTQ

[Michael Spiers <mikes@specnet.com>]

I've been having an idle problem with my TQ for many months now.  After a bit
of driving (half hour or so), the idle in the TQ will drop from it's normal
950RPM's to around 500RPM's.  If I shut the car off & restart it, the problem
is cured.  I figured it was a screwed up idle switch, but never had the time to
futz with the thing.  Well, it's gotten pretty bad (and pretty annoying) so
this weekend I pulled the idle/WOT switch out of the car, pryed it open, &
resoldered all the contacts & cleaned up the WOT switch best I could (the WOT
on my car has _never_ worked, now it does!)  Well, the WOT now works, but there
is no change in the idle problem.  I am getting continuity thru the switch when
the idle drops, so it's not a problem with the switch itself.  How can you test
the connection at the idle valve for continuity?  As soon as you unplug the
valve the circuit is broken & is not closed until you shut down the car &
restart it.  Would connecting a wire to the leads to the valve & hooking up an
LED to it disturb the function of the valve?  On the same subject, would a
faulty O2 sensor cause this type of problem?  I haven't checked it yet...
 Anything else that may be causing this problem?  TIA for any
thoughts/suggestions.

-- 
-Mike
mikes@specnet.com
mks107@psuvm.psu.edu
87 5000CS TQ - Metropolitan Washington, D.C.
84 5000S - Boulder, Colorado
90 80 - Bethesda, Maryland