'87 5KCSTQ: What sensor is this ?

["Kurt Wesseling" <kwessel@enm.maine.edu>]

Hi folks...

The $64,000 question of the day is, what is that small threaded
sensor on the top right front of my '87 5KCSTQ engine?  It goes into
the aluminum block, is upright and has one blue-green wire going to
a single brass connection terminal on top of it.  It is above what
(I think) is the coolant temp sensor.  That one has two wires going
to it. Is the single wire sensor the ISV temp sensor? 

Reason I ask is because intermittently my idle climbs to around 3k.
(talk about unintended acceleration ! heh) When I lift the hood, or
bonnet for you across-the-ponders, and pull the blue-green wire off
the sensor, the idle settles down to about 900 rpm.  Once
reconnected, it stays down--for a few days.  Cleaned ISV, it looks
ok.  Is this sensor going south? 

--Kurt

______________________________
Kurt Wesseling
Technical Support Center
The Education Network of Maine
800-696-4357
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