Grumbling Puma

[Deleted User 797]

My Puma (2021 155 auto) is grumbling !!!! I've noticed when cruising along at 30 ... 40... 50 (i e. not under acceleration) I can feel the car is rough... spluttering?... misfiring? can't really describe it better but the drive no longer "feels" or sounds smooth. Makes me think of a faulty spark plug but as the engine only has three i'd a thought the loss of one and the car would throw a fit. Anyone had anything similar?