2005 Mercury Sable High Idle Problem

2005 MERCURY SABLE
46,150 MILES • 6 CYL • 2WD • AUTOMATIC
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JEPOHLMAN
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Sitting in park or at a light the engine idles at about 700 rpm without any problem.

If you put the car in neutral while going down a hill the idle stays up in the 1800 rpm range if you're doing around 65 mph and then drops down to around 1400 at about 50 mph.

If this is done around 30 mph the idle drops down to the 700 rpm range where it should be.
Feb 21, 2009 at 1:12 PM
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JACOBANDNICKOLAS
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Hi:
Has the check engine light come on?
Feb 21, 2009 at 7:35 PM
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JEPOHLMAN
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The check engine light hasn't come on.
Feb 21, 2009 at 11:36 PM
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JACOBANDNICKOLAS
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If there is no check engine light, check for vacuum leaks. Make sure none are disconnected dry rotted, or broken.
Feb 22, 2009 at 12:41 PM
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JEPOHLMAN
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No vacuum leaks found. Pulled the IACV and there wasn't any carbon buildup on it to speak of.

Resistance was 9.9 ohms.
Feb 25, 2009 at 8:25 PM