The car is jerking when i drive in low speed at low gear

[Ivar]

I have a Toyota Camry 1992, XLI with manual gear. I bought it 2 months ago, and i am very happy about the car, the only problem i got is that when i drive in 30km/h in 3rd gear the car sometimes starts to jerk a little, it also happen in low speed in 4th gear, i got the same problem when i let go of the accelerator a little too fast, and when i pump on the accelerator. Does anyone have any clue on what the problem could be.

[Kep]

What is the RPM when you feel the jerking?

[Ivar]

It's from 1500rpm till 2000rpm. I did a little testing on the engine and it looks like it's the ignition system. When the car is in free and i hold the accelerator steady the rotation speed is going up and down. It gets less when i go higher and higher, but when it's about 1600rpm the rotation speed goes up and down like crazy (from 1500rpm to 1650rpm)