RE: increasing idle

[glen powell <gpowell@acacianet.com>]

There is a temp sensor that controls the idle system and this sensor
can go bad and cause these symptoms. Far less expensive Vs the
ISV or control unit, so it's worth a try, BTDT, it fixed it for me.

-glen

My '86 5kcstq does basically the same thing as your 87 is doing.

It's somewhere in the idle stabilization system. I've tried 
everything except replacing the ISV (idle stabilization valve, which 
I cleaned and which _appears_ to operate correctly when voltage is 
applied to it) and the ICU (idle control unit, which I did remove and
examine for any obvious signs of internal damage).

Both are expensive items to replace.

A number of sensors feed into the ICU; I've checked all of mine, and
they all work. What I have not done is check the wiring path between
each sensor and the ICU socket.

I'm hoping to eventually hook up with someone who will either
loan me an ICU and ISV known to be operating correctly to test
in my car, or swap with someone in a parking lot for a 5-minute 
test.

If you get yours working properly, let us know what it was that
did the trick!

hth,
doug

--
-Douglas Hurst Quebbeman (dougq@iglou.com)            [Call me "Doug"]
74 100LS Auto, 77 100LS Auto, 84 Coupe GT, 86 5Kcstq
"The large print giveth, and the small print taketh away."  -Tom Waits