Strange idle problem

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Jun 20, 2009 | 06:02 PM

TransAm Mania

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From: Cicero IL

Strange idle problem

2003 LQ9 ASA Cam 226/236 110LSA .525 .525 Ls6 Intake, headers (no AIR tubes or Smog pump) No EGR. PCM tuned for application.

My idle normally is steady around 800-850. Every 3 to 5 minutes, the idle will drop below 500. Even when I'm coasting with the clutch disengaged, the idle will be extremely low causing me to loose power steering and vacuum for power brakes. What is causing my idle to drop? Could it be that the EGR was never programed out of the PCM or possibly EVAP system related? Please help

Thanks

Jun 20, 2009 | 06:53 PM

rao

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From: Naperville, IL

Has it always done this or is it new?

I'd check the timing table in the idle area, large gaps there can lead to an unstable idle like you described.

Jun 20, 2009 | 07:15 PM

busta9876

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From: West Plains, Missouri

Quote:

Originally Posted by TransAm Mania

EGR is not commanded during closed throttle. EGR should not effect your idle. Could this be timed with an electric fan turning on? Causing an increased load on the engine? Is the VSS working properly. As mentioned, this new problem or always been there.?

Jun 21, 2009 | 07:25 AM

TransAm Mania

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From: Cicero IL

I recently got the car running, about a month ago. Its always done this. As for the VSS, I installed a new one as the trans did not come with one. Its connected to the PCM but I have not yet installed an electronic speedometer.

Jun 21, 2009 | 11:17 AM

Mikey 97Z M6

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I would check to make sure the PCV system is hooked up and operating correctly. I made a mistake with my LS swap and hooked up the PCV wrong and it caused alot of idle problems. Yours sound similar to the issues I had.

Mike

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