thanks for the input sir civicvti.

but this problem wasn't present when i bought the car as 2nd hand, taking into consideration that the air filter was already changed to simota kit. i only noticed this problem almost a year after. the car was running perfectly smooth before.

as assessed by the mechanic, he said that the worn out sparkplugs and the dirty maf was the cause of said abnormal behavior (jerking of the rpm).