C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

High Idle/ setting problem

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Old Nov 1, 2004 | 10:53 AM
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Default High Idle/ setting problem

I've repeatedly tried to set the idle speed on my recently rebuilt engine in an '85. Following the Chevy manual, the engine will not maintain the 'SET" idle speed. TPS and IACV are new and adjusted per manual. Could the "re-programmed" prom be the culprit? I can't see anything but black soot on the O2 sensor, so I'll assume this sensor is ok or plays no role in the high idle (1200 rpm) problem. Any ideas, please. Thanks, Jack
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Old Nov 1, 2004 | 08:34 PM
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From: Database Error Indiana
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If the O2 sensor is black it may no longer be working. Did you put in a big cam? You will have to run at higher rpm than the base idle set calls for if so. Did you try and set the idle screw in till it runs good and reset the TPS? I had to do this when I did cam/intake mods. A scan tool will really help set the idle.
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Old Nov 1, 2004 | 09:48 PM
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From: Fremont Oh
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Sounds to me like you may have a vacuum leak if you cannot get it to idle down... Did you recently change your cam and heads manifold?

Just a thought...

Mo
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