I’m having similar problems myself. 2015 MkIII vRS petrol, manual 90k miles at OEM standard (no mapping etc). I’ve owned the vehicle since new.
Only recently began, misfire under moderate / heavy load, but a little more gas brings on the EPC light. Once EPC on, the engine runs with a pronounced shuddering. Turning the car off and then back on resets the vehicle. Seems to be getting progressively ‘worse’ (or it could be that I’m just noticing it more).
I’m not so great with in-depth understanding of the vehicle: I’ve had it serviced annually. Had the water pump changed at 70k miles and been battling with the usual coolant / oil issues. Not sure if any plugs or coils have been changed, I haven’t kept the service records.
tristan, did your issue get resolved? Anyone have any pointers before I go to my mechanic? I’ve got what I think is a pretty reliable one with good familiarity on VAG cars.
cheers