Hello there There is a chattering noise coming from what sounds like the supercharger while it idles and at low rpm. When I give it more rpms the sound goes away, It is not any of the pullies, I've looked at them. How do I know if it is in fact the supercharger, and if it is, is it possibly only the noes dirve. Otherwise it still runs fine except for the annoying noise. The car is a 1994 Olds 98 V6 3800 supercharger Thank you John C

Without a general description of what the noice sounds like, squeal as compared to knocking, it is impossible to help you. Engines make a lot of different noises, so try and help by describing noise. I would suspect it is belt related, or tension pulley related as these are RPM variable noises, belts tend to slip when you accelerate and can be quite loud with a serpentine belt as example.
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Check out related help links to troubleshoot these problem:----Click the link below:---Idles Fine but RPM jumps in drive mode? http://technoanswers.blogspot.in/2012/07/idles-fine-but-rpm-jumps-in-drive-mode.html
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http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
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http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

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Cruise Control stops working, Excessive cranks to start the engine and RPM goes max 2500 http://whoisbyme.blogspot.in/2012/07/cruise-control-stops-workingexcessive.html

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1990 Toyota 4Runner: Engine cuts off when reaches 2000 RPM?

http://whatisbyme.blogspot.in/2012/05/1990-toyota-4runner-engine-cuts-off.html

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1999 Toyota Camry: Erratic stalling and high engine RPM at idle?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

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These will help.
Thanks.

are you reading your rpms right....5-6000 rpms should equal 70- 85 mph....that is certainly not idle speed....invest 20bucks in a Haynes manual----it is good reading

Does the oil light come on or the knock occur during the engine warm up after a cold start?
There could be a couple of problems causing the issue. You could have an oil pressure pump or pump pressure regulator sticking. I would have a mechanical oil pressure gauge installed and verify oil pressure at idle and 2500 rpms to make sure oil pressure is in normal ranges.
You could also have excessive piston rod bearing, crankshaft bearing or cam shaft bearing wear that will cause oil pressure to drop too low to prevent the rod knock your hearing at 2500 rpm.
You said a knock and not a ticking noise,so I don't believe a lifter is the issue at 2500 rpm.
Start with the oil pressure check and go from there.
Let me know.
Regards,

have your TPS sensor looked at since that controls your idle and rpms. It sounds like it's causing your rpms to drop too low

check your timing chain or belt might be loose and or your belt tensioner is not working

its sound like one of those prolbem that you will have to run it un till it breakes.if it dusent bother your car wile it run i would not worry .

sounds like you either have a brake light out or you need air in your passenger side rear tire. jk. i wish i could help.

Idle Air Control (IAC) motor is sticking.You can try taking it off and cleaning it but most likely will have to replace it.