High idle My 300zx idles high right after starting at aorund 2500 rpm then drops to about 1500 rpm after a minute or so. Is ther any way to adjust the idle? Or is ther something else going on? Thanks!!!!

All the above is normal , except 2000rpm is a little high at idle . can be adjusted down to 1500rpm. the computer adjusts the engine speed . in drive the transmission loads up the engine idle drops to 1000rpm . in park engine unloaded rpm increase all normal.

Cars are design to run at a higher idle at start up to warm them up quick. There is a sensor that reads water temperature and tells your car's computer how fast to idle. Your RPMs seem slightly high but not out of the norm. Does idle ever drop to around 600/800 after about a minute? If not, your engine temperature sensor maybe defective.

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
---------
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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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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These will help.
Thanks.

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
---------
Engine cuts out at 3000 RPM?http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

---------

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

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

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

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

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

---------
1987 Toyota Camry: RPM Drops going Up hills?http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.html

-----------
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

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

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

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

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

---------
1995 Toyota LS: Misfire at idle or low RPMhttp://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

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

----------
These will help.
Thanks.

I have a Nissan 300zx twin turbo 1990.... The engine and car are in very good condition ... well serviced... The idle speed will not go below 2000 rpm can you help as there is no manual adjustment...????

You may have a bad control valve or regulator. Did you adjust the idle properly?

1. Disconnect the connector on top
2. Adjust idle to around 650-700k rpm
3. Reconnect the electrical connection

After reconnecting, the idle should jump up around 700-750k rpm.
The idle screw is fail safe setting in case the ecu cannot set the idle. The rpm's set by the idle screw are supposed to be below the ecu/stock idle.

If this doesn't work, you may have a dirty or bad Idle Air Adjuster and/or Air Regulator. For information on cleaning that, you can refer to this page http://s95014253.onlinehome.us/63104/157335.html

You can test the IAA by supplying power to the plug with the car off. Listen for any clicks or humming. That will signify that it still may be working but is possibly stuck. The Air Regulator is for high idle for warming up your car. It has a bi-metal spring inside that rotates a disc closing off an airway to bring idle to normal after a couple minutes. If it dies it will stay open and give you permanent high idle. If it gets clogged usually no high idle for warm up.
You can remove it and peer through the end. If you see a thin sliver of light, it's open. Connect 12 volts + & -, wait a few minutes and see if it's now closed. If not, it's likely dead. It can be opened and cleaned if that's the issue.

Make sure your throttle cable is not bound up on anything. Also where the throttle cable ends at the throttle body make sure it moves freely and there is nothing obstructing its movement..Rpms are a little too high to be a vacuum leak.

sounds like the tps is bad or idle control motor

If the car idle on high rpm check if when you will step on the gas pedal over 2500 3000 rpm the car will start shaking and the will die if thats happening then check your mass air flo sensor ,or if there is no air leak that avoid the mass air flo sensor

Try to look for an idle adjustment screw. if not. The idle position sensor may be bad.