The symptoms you describe are very typical of a blocked diesel particulate filter. I had a similar issue with my old Peugeot. Reduced power and smoke, especially under acceleration, are key indicators. Have you noticed any changes in fuel efficiency recently? Also, is the engine light illuminated?

A sensor fault is possible, but the reduced fuel efficiency and smoke strongly suggest the diesel filter is the main issue. The engine light may well be related to the backpressure caused by a clogged filter. At this point, I'd recommend getting it checked by a workshop. Continuing to drive with a defective filter can cause further damage.

Yeah, engine light's been on for a while, figured it was just a sensor fault. Fuel efficiency has definitely taken a hit. You think backpressure could be the culprit too?

Thanks for the input. Dropped it at the shop and you were right. Diesel filter was shot. Cost me 1550€ to replace. Now she runs like new again.

O meu Mini One a diesel de 2006 tem-se comportado mal ultimamente. Notei uma perda de potência e está a fumar quando acelero. Tenho quase a certeza de que é o filtro de partículas diesel a caminho do fim.

Mini One Diesel a funcionar mal