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

Engine idle issue, Hunting

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Old Jan 7, 2012 | 07:05 PM
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Default Engine idle issue, Hunting

Been working on this for several months. After replacing a head gasket, I started having problems withe the engine hunting while idle. I replaced vacuum lines, set timing, replaced plugs, wires, distributor, coil, etc.. The engine still wants to hunt between 6 & 8 rpm. Any new ideas?
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Old Jan 7, 2012 | 07:19 PM
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Have you checked for leaks at the intake manifold?
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Old Jan 7, 2012 | 09:37 PM
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Originally Posted by 1986coupe
Have you checked for leaks at the intake manifold?
How ho I check for leaks at the manifold?
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Old Jan 7, 2012 | 10:23 PM
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slow egr
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Old Jan 7, 2012 | 10:25 PM
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Originally Posted by Bredd1
How ho I check for leaks at the manifold?
check for loose or broken vacuum lines, evap lines..
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Old Jan 7, 2012 | 10:35 PM
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Originally Posted by pewter99
check for loose or broken vacuum lines, evap lines..

Holy moly. Looks who's posting in C4 tech.
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Old Jan 7, 2012 | 11:58 PM
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Originally Posted by oldalaskaman
slow egr
Slow EGR?
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Old Jan 8, 2012 | 08:01 AM
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What do you mean slow EGR?
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Old Jan 8, 2012 | 09:49 AM
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Originally Posted by Bredd1
Been working on this for several months. After replacing a head gasket, I started having problems withe the engine hunting while idle. I replaced vacuum lines, set timing, replaced plugs, wires, distributor, coil, etc.. The engine still wants to hunt between 6 & 8 rpm. Any new ideas?
What year? I would also check the IAC. If the problem started after the work was done, 9 times out of 10 there is a relationship.
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Old Jan 8, 2012 | 04:05 PM
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Originally Posted by sailorsteve
What year? I would also check the IAC. If the problem started after the work was done, 9 times out of 10 there is a relationship.
I pulled off the throttle body, cleaned it and replaced the IAC. Also went through proceedure to set idle speed and set TPS to .54 volts.
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Old Jan 8, 2012 | 06:37 PM
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if the egr is cruded up it will function slowly, causing your idle to flucuate
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