Hi Eranga............. just bought a N16-2003 model recently myself
What u are referring to is the Mass airflow sensor placed just after the air filter. i have heard that it qives quite a bit of problems on this model........ so better replace it along with the air filter and see what happens.
Its Rs.16K at AMW but i saw one guy selling 2 brand new sensor got down from japan (4-pin ones) for Rs.4k at
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once u do replace the sensor always check and maintain a clean air filter.
Cheers Mate