Nissan Repair: 1987 nisson pathfinder, throttle position sensor, air control valve

Question
after driving for awhile and I come to a stop light the engine idle speed drops to 500 rpm. This is a 3.0 liter v6 with manual 5 speed, what do you think would cause this problem ? Thank You Dale Brooks

Answer
Throttle position sensor or the idle air control valve.  Since you say that it does not do it all the time.  I assume that means after it gets warm it does what you describe.  So, once it is out of choke mode the engine idles down too much and that would be one of the things I mentioned.