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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
there is a small vacuum switch that blocks vacuum retard going to the distributor to raise idle about 200rpms for about a minute after a cold start in your '87 but there is no switch that raises idle for 10 minutes.

there is an aluminum valve sometimes called the auxilairy air valve to the right of the WUR that bypasses air from the intercooler around the throttle body into the intake manifold to raise idle around 800rpms relatively when it's cold. It slowly closes and idle speed gradually lowers over a mantter of minutes depending on ambient temperature.
i'd guess this device is stuck closed and may be your car's problem.

when it's very cold out the thermal time switch in the left side chain case cover opens the cold start injector under the throttle body while the starter motor is cranking. dwell time for that injector depends on how cold it is and how long and how often the starter motor has been cranking.
it has nothing to do with idle speed.

the other sensor you mentioned is in the right side chain case cover and it disables the lambda emissions system while the motor is cold so it will run stronger and smoother but it doesn't make it idle higher.
Old 07-30-2011, 02:21 PM
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