I think (not 100% sure) that when my '89 323 was doing that, it was a really loose spark plug. Just replaced spark plugs with new ones, and got new wires too. If that doesn't help let me know.
What kind of Jerking is it doing?.. like it's going to die? I have a '89 323 and i would have my foot on the pedal pretty hard sometimes and it would jerk like it wasn't getting gas, and wanted to die. I'm going to have to think about what it is i did to fix it but...i'll get back to ya