When my 89 turbo is idiling the oil pressure is around 2 kg-cm2 but when driving it goes up to an average 4. What does this mean? is it regular to do so?

Thanks

 

So, about 28 psi at idle and about 56 psi above 3k RPM. That isn't far off from the FSM specs, which is often the case with old oil pressure senders. I wouldn't worry unless you confirm those numbers with a mechanical gauge.