Idle control I have a 1988 nissan pick up truck that is idling high. It is idling at about 3000 rpms in neutral and I would like to know where the idle control is so that I can lower it down to 1000 to 1500 rpms.  What do you recommend? and what is the ideal idle?

-scan for trouble codes -check air filter --map sensor [clean if dirty ] vacuum leak --cat converter--fuel filter

DOES IT IDLE HIGH WHEN HOT?IF IT IS SO THAT'S NOT THE
IACV(IDLE AIR CONTROL VALVE) .

For this types of problem,there are few help inks to troubleshoot the problem.Click the link below to go through the troubleshooting procedure to resolve the issues :----Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html-----------van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html
--------------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Car still runs Rough after tune up? http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html
------------Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed? http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html
----------High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html
------------Engine Backfires? http://technoanswers.blogspot.in/2012/02/jeep-backfires.html----------- Nissan stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

-----------
Nissan Pathfinder Backfires? http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-backfires.html
---------How to adjust rpm? 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
----------This will help.Thanks.

replace the temputer sensor it dont know to choke the motor or not so to speak

If the vehicle has a automatic transmission, check the Neutral Safety Switch. If defective from wear it could be sending incorrect signals to the Electronic Control Module which in turn sends signals to the Idle Air Control. It will make the computer think the transmission is in gear and lower the RPMs and then when the transmission is actually in gear the physical load will lower the RPMs even more. To check, set the parking brake and move the gear selector to Neutral and check the RPMs to see if the engine maintains a constant 650 +/-. Next, shift to Drive and check if RPMs drop to and maintain 500 +/-. If it does then you have diagnosed the problem. The original equipment Idle Air Control motors rarely wear out.

IAC - Idle Air Control sounds bad

idle air control motor or just a plain old vacuum leak

try clean idle speed control.

turn the idle screw down on the carburater

you can turn your idle down. i have the same car and it was doing the same thing. i had someone adjust it and it hasnt had a high idle since