Many DF084 engines came with the Lucas DPC pump. These are prone to micro-leaks from the throttle shaft. Better solution: Swap to a Bosch VE pump from a Renault J8S or a Volvo D24. It is a bolt-on modification (with minor bracket work) that transforms reliability and allows for a true "smoke screw" adjustment.
Exhaust Gas Recirculation (EGR) valve position sensor circuit actuator relay control circuit renault df084 better