Nissan Repair: engine stalls when I stop, mass airflow sensor, air control valve

Question
I have a 2001 nissan sentra 2.0L se. It stalls or stumbles at idle when I stop, or it shuts right off if it isn't in gear. This seems to happen only when it is warmed up. Also when I run the air conditioning the idle stumbles and drops to about 400 rpm's but it dosen't usually shut off. This repeats itself about every minute or so. The car acts fine as long as you are moving, it accelerates ok and maintains speed without any problems. The problem only happens at idle.

Answer
John,

The throttle body probaly needs to be cleaned and the idle air control valve needs to be replaced.  After you do these it should be good.  Now, there is a remote chance that the mass airflow sensor is going out but you would need a digital volt ohm meter and a Haynes Manual to provid the procedure and values to verify the mass airflow sensor is good or bad.  For some reason the computer does not set a code for the mass airflow sensor?  Anyway, those are the options and this is the order I diagnose them in.  The idle air control valve is much less expensive compared to the mass airflow sensor.  rockauto.com or courtesyparts.com are both good sources for parts and are much cheaper than the dealer or your local parts store.