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surge at idle !!!
Topic Started: Jun 16 2010, 04:13 PM (631 Views)
porsh911t
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[ *  * ]
i have a g10 in my mini , when the car warms up after driving,when i come to a stop the engine surges, also it idles at around 2,000
its a 1994 california car.any help would be appreciated. thanx chuck
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mcmancuso
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I'd almost guarantee a vacuum leak, hose is really cheap, replace all the rubber vacuum lines. In the small possibility that doesn't fix it, then check the IAC(idle air control valve), MAP(manifold pressure sensor) and maybe TPS(throttle position sensor). Good luck :)
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Memphis metro


Is the check engine light on? If so you can put a fuse in the fuse panel and count the blinking light to determine what the engine codes are and post that information here and will help.
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crankcase


I second what mcmancuso wrote. Check the brake booster vacuum line as well, it often gets stoped up. There are some recent threads (within last 2 months) on high idle that will give you details and some ideas (IAC problem, coolant lines at throttle body stoped up), just do a search.
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mcmancuso
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Crank reminded me about the coolant lines, check those make sure they're free flowing, and as a last sensor to check, the coolant and intake temp sensors that are in the throttle body and air cleaner assembly. Those will cause high idle (usually not 2000RPM high, but can contribute) due to the car thinking its still cold and running faster to warm it up.
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mwebb
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FOG

MAP sensor can not cause this .
-----------------------------------------------------
if it is surging
the TPS closed throttle switch is working as designed

it is in DFCO decel fuel cutoff , the ECM thinks you are coasting down hill , foot off the throttle with high engine RPM
so the ECM shuts off fuel
until the engine RPM drops below a threshold , around 1250 RPM
then the ECM enables fuel , RPM goes back UP
repeat

so
there is pirated air getting past the throttle plate
question is
where 's it coming from ?
==============================================================
can be from the PCV if it is stuck open , most people do not think of that
not saying that it is
i dunno ,i just know there is pirated air getting by the throttle plate
Edited by mwebb, Jun 16 2010, 09:25 PM.
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