Mercedes Citan Diesel Engine Trouble

Okay, so mixture preparation error can be a pain Since you are experiencing reduced power, rough running, and stalling, a defective fuel injector is a strong possibility Think of the injectors as tiny sprinklers that spray fuel into the engine If one is clogged or broken, it will not spray the right amount, causing problems The oxygen sensor or mass airflow sensor issues you mentioned could also contribute to mixture problems, but are less likely to produce stalling Have you noticed any changes in fuel consumption recently Also, has the engine started making any unusual sounds, like ticking or knocking

No unusual sounds that I can pinpoint, and honestly, it is hard to tell about fuel consumption since the power loss is so noticeable If it is a fuel injector, is there any way to test them myself, or is that strictly a job for a mechanic with specialized equipment I saw some fuel injector cleaner at the parts store; would running a bottle of that through the system maybe help, or am I just wasting money

Fuel injector cleaner is like taking a multivitamin it might help a little, but it will not cure a serious illness With those symptoms and the mileage, I would say the risk is too high that you damage your engine, and cleaning will be a waste of money and time Testing fuel injectors properly usually requires specialized equipment Given the stalling and rough running, I suggest taking it to a workshop They can run diagnostics and pinpoint the exact issue it could very well be a faulty injector as suspected, and they can confirm that for sure

I took it to a trusted mechanic It WAS a defective injector Replacement cost me around 515€, but now the engine runs smooth