2016 Citroen C4 16 plate 1.6 diesel intermittent rough running

Started in 2022, engine will intermittently lose power and run rough rev counter fluctuates, usually lasted around 5 mins or so , initial diagnosis was Dpf issue, went into Citroen in October 22 for new sensor and pipes. June 23 same issues start up goes back into Citroen to be told that due to the pipe being screwed on wrong new Dpf needed, £1800 later I get the car back, 3 weeks later problem starts again loss of power runs as if it’s not getting enough fuel rac diagnostics came back as pre catalytic converter issue, engine runs rough for around 2.5 hours then as if by magic runs like normal, now back with Citroen no fault codes found no issues when on test drive. I can drive for weeks with no issues then bang it’s back again , will then clear then 2 days later coughing and spluttering another month could go by before it happens again only constant is I’ve noticed if it does it it will be around the 6 or 7 mile mark.