How do you do idle relearn for 98 altima

Wheel nuts loose, or stones in hub caps, do you get the noise rolling down hill ? , if not its engine, retrace your repair.

An IAC (idle air control) motor is designed to adjust the engine idle RPM speed by opening and closing an air bypass passage inside the throttle body. The cars computer or PCM (powertrain control module) receives information from various sensors and will output signals to adjust the idle air control motor in or out to adjust engine idle speed by controlling engine idle air. An idle air control motor can fail one of two ways, either the motor short circuits and stops working or the motor will develop high resistance and cause the idle air control motor to react slowly, either failure can cause the engine to stall at idle. When a trouble code scan is performed it sometimes won't always detect a failed or weak idle air control motor.

the dreaded P0507, have you had your throttle body cleaned lately? I did clean a neighbors TB while doing other maintenance things to it, and this popped up-and it was miserable getting rid of it. You have to do a 'relearn' procedure (about a million times or so, it seems) and DO NOT take it to a dealer-they will just charge you $100 and tell you to install a new throttle body (not cheap). They know this is a problem, and act like you have done something wrong for merely cleaning a dirty TB. It can and will go away if you do the 'relearn' procedure-read this post for information on how to fix it. it is just annoying but does not have to cost anything to correct. His took MONTHS to reset, but it did, and I did a lot of research on this and can assure you it is not what the dealer would have you think it is-they will try to separate you from your money for this code. read this:

http://www.nissanclub.com/forums/2002-2006-nissan-altima-discussion-2-5-3-5/243119-p0507-idle-control-system-rpm-higher-than-expected.html

Problems with Nissan 2005 Altima include-Crank shaft position sensor with ECU reset, ECU Factory reset from Dealer, Low Fuel pressure requiring fuel pump replacement, Replacement of ignition coils causing misfire during start-Catalytic Converter Recall-Oxygen sensor on exhaust-Leaking Valve cover gasket-Radiator failure due to plastic top & Bottom (Constantly adding water to reservoir?)

if the throttle body was replaced or cleaned or battery was diconnected for an extended period then the idle value you needs to be relearned.im not aware of any way to do this without a scan tool that supports this function or taking it to the dealer .

when this is done idle air volume needs to be relearned .to my knowledge dealer only procedure .i could be wrong but i dont think aftermarket scanner software supports this.more good news.po420 you need a cata lytic converter.p2135 and po 123 you need a new throttle chamber assembly.

Clean throttle body first, make sure you disconnect battery foe about 30 minutes so PCM can relearn to cleaned throttle body.

this problem is caused by a sludged up intake idle speed control valve to clean it follow these instructions.
, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

need idle relearn or throttle chamber

The IACV is located near the front of the head on the intake side, just below the #1 intake runner.