Hi there auto gurus.

Just want to know what could be the possible problem/s that causes this jerking RPM problem and causes the (almost) shutdown of engine after hi rev either on highways or even at a standstill??

car details:
'97 Nissan Sentra SS
approx 140K mileage

Had a pms at speedyfix wherein i had a change oil, sparkplugs and cleaning of the MAF (?). Changed the simota ail filter recently.

The car engine doesn't sound normal when this problem occurs. Any ideas sirs/madams??