Engine idles up, down and low while under 1000 rpm

The chance is good that the oil was replace with thin oil. If the car idles lower than it did before the service it can also be the cause and need to be adjusted to higher rpm. No immediate damage to the engine forseen but need to be rectified asp especially if the car is going to idle frequently or for extended periods.

It,s either not getting enough gas or not enough air. Check has and air filters.

No,only on carburated engines it,idles down to the set point,on yours,it's fuel injected,pushing gas pedal won't kick idle down,should go down after a certain amount of time,does it automatically,If you start and drive a 5 mile ride and stop at a stop sign,it should idle at it's set point if there's no engine problems,which may be.5 to .7 on your tac.When you normally first start,it will idle between 1000 to 1200 rpm's,don't push on gas,let idle say 15 seconds,put in drive and go.

True of many cars. Happened to me too many times, fourin
or domestic.

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
---------Mitsubishi Lancer rpm needle bounces? http://technoanswers.blogspot.in/2012/02/mitsubishi-lancer-rpm-needle-bounces.html
--------How to adjust rpm on 2009 dodge charger SRT8?

http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
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Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

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Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

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High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

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Jetski Sputters and Low RPM? http://whatisbyme.blogspot.in/2012/07/jetski-sputters-and-low-rpm.html

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Fuel Injection Problem And RPM suddenly increases http://whatisbyme.blogspot.in/2012/07/fuel-injection-problem-and-rpm-suddenly.html

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2005 Toyota Highlander: Engine runs hard RPM below 3000? http://whatisbyme.blogspot.in/2012/05/2005-toyota-highlander-engine-runs-hard.html

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1987 Toyota Camry: RPM Drops going Up hills? http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.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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1995 Toyota LS: Misfire at idle or low RPM http://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

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Lexus RX: Tapping noise under Valve Cover At Low RPM? http://technoanswers.blogspot.in/2012/04/lexus-rx-tapping-noise-under-valve.html

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These will help.
Thanks.

Probably two different issues.

The code is saying the computer sees the engine RPM is too high when shifting between park neutral and drive.
The rough idle would be something else.

Do you have the idle speed turned up to keep it from dying? Because it is high. Check engine light on? Have you checked for vacuum leaks at the gasket under the throttle body? How does the car run under acceleration? You might have a worn distributor shaft.

it could be a idle air sensor.

Check the fluid.Change the fluid and filter and see if it gets better.If it does then I would recommend a fluid transfer.This will transfer the old fluid and add new fluid.Hope this helps.Good luck.

IAC motor