Mercedes X Klasse Diesel Engine Running Rich

Sounds familiar, though it was my old BMW that gave me grief like that Similar symptoms, especially the rough running and the check engine light popping up First thing I'd check is your air filter A clogged filter messes with the air-fuel ratio and can cause all sorts of problems Also, when was the last time you looked at the oxygen sensor A faulty one will throw off the engine management system and make it think it needs more fuel Has the air-fuel ratio been checked recently

Thank you for your response I appreciate the suggestions Regarding the air filter, I replaced it approximately 10000 km ago Is it possible for it to become clogged so quickly As for the oxygen sensor, I have not checked it recently Where is the oxygen sensor located, and how can I test it to determine if it is functioning correctly

10000 km might be enough, depends on where you drive, dusty roads will clog it up fast As for the oxygen sensor, it's usually located in the exhaust system, before and after the catalytic converter Testing it properly requires specialized equipment, a multimeter at the very least, and knowing what readings to expect Honestly, given the symptoms and your initial suspicion of a fuel injector issue, and especially since the check engine light is on, I'd strongly recommend taking it to a workshop They can diagnose the problem accurately and avoid you throwing money at parts you don't need

I sincerely appreciate your advice I took the vehicle to a certified Mercedes-Benz mechanic for a comprehensive diagnosis As suspected, one of the fuel injectors was indeed defective, causing the engine to run too rich The mechanic replaced the faulty injector, and the check engine light is now off The total repair cost was 515€ The engine now runs smoothly, and the fuel consumption has returned to normal Thank you again for your guidance