Fiat Ducato Idle Problems & Solutions

Hello, I'm new here.
I got the address from a Fiat Ducato.

My vehicle is a Ducato 2.5L TDI Cat ECO, first registered in November 1994.

After unsuccessfully searching various Fiat Ducato forums, I would like to ask for help here.

After the engine warms up, it runs with a sawtooth pattern at idle.
It oscillates up and down within a consistent speed range.

Has anyone among the forum members ever experienced similar behavior?
What approaches are there for: a) locating the error, and b) fixing the error?

Thank you in advance for any suggestions or advice.

Peter.

Hello.
If my memory serves me correctly, your Ducato from '94 still has a purely mechanically controlled fuel injection pump. Therefore, the problem must be in the regulator itself, possibly due to play or sticking control weights. If that's the case, the only solution is either repairing the pump or replacing it. However, more information about the vehicle would be helpful, such as the pump type and mileage, etc.
Best regards,