Erratic Idling

My Nissan k11, engine CG10. My idling is unstable and sometimes it turn off the engine. I just found that it start emitting black smoke. For me its cause by excessive fuel consumption.
I remove and clean the air flow meter thoroughly. Its ok for few days only and now the problem persisting again.
Do I need to replace the air flow meter?

throttle body resolder?

Check/clean all plugs/connections to the throttle body, try the resolder, check/replace fuel filter/spark plugs.

If those fail, try this:
http://micra.com.au/community/message.php?messageid=87183

resolder? I don`t understand

http://micra.com.au/technical-articles/cg13de-throttle-body-resoldering-guide.php

Hi Big John. I just checked it. I have tested and the circuit is good.
Need more info

What else have you tried?

I note that when the engine is hot or when I`m driving for long distance that the idle become unstable and turn the engine off. I removed the catalytic inside the manifold.
Now it look better. I have to drive the car for long distance to see if the problem persist.
Will confirm later.

Hi Big John,
At cold the idle is ok. I drive almost 64kms and the engine cut off 3 times only.
I note that when I stop suddenly the idle goes very low and the engine cut off. When I stop normally, the engine idle is normal.

The fuel consumption is good
No erratic idling
Good accelerations
No misfiring

As a mechanic, I don`t think the problem associate with air flow? What you think?

Have you changed your fuel filter lately?

Not recently. 4 months ago I renewed it.
Its nearly 4 days and I don`t have any problem now. Fuel consumption is good, no erratic and idle is stable