Erratic running and increased fuel consumption in 2013 BMW 2 Series diesel - possible cause crankcase ventilation?

Sounds very similar to the mess I had a few months ago with my 2016 BMW 4 Series diesel. The symptoms were almost identical to yours, and let me tell you, it was no walk in the park. In my case, it was actually the crankcase ventilation valve that had given up the ghost. That's what caused all the problems and the repair really wasn't a piece of cake. I took the car to a garage at the time and the guys were visibly relieved once they had diagnosed the problem. It was pretty serious, but in the end everything was ok again. Hope your car has the same problem, then at least you'll know what it is. All the best, hope this helps you!

(Translated from German)

Hey, thanks for your quick reply! I'm a little reassured to hear that you had a similar problem and then got it solved after all. Do you happen to remember how much you had to pay for it? And has anything else come up since then that might be related to the crankcase breather valve? Thanks again and have a stress-free evening!

(Translated from German)

Hey, no problem, that's what we're here for! To answer your question, the cost of repairing the crankcase breather leak wasn't exactly a bargain - I had to pay €425. But since I went to the mechanic, everything has been running smoothly. The crankcase ventilation faults have been fixed and I haven't had any further problems with it since. Hope this info helps you and you'll soon have a worry-free ride again. Take care and don't hang your head!

(Translated from German)

Great, thanks for the info! That really helps me. Even though €425 is quite a lot, I'm glad to know that there shouldn't be any further problems after that. I'll try my luck with the garage again and hope that they get the problem under control just as well as you did. Then my little runabout should soon be as good as new again. Have a relaxing evening and always have a safe journey!

(Translated from German)