BMW 4 Diesel: Stalling & Air Pump Issues, Help Needed

Hi there! I have some experience with car maintenance and had a very similar issue with my 2019 BMW 3 Series diesel last year. The symptoms you're describing sound exactly like what I went through with mine. Took it to my regular workshop and it turned out to be a faulty hose connection from the pump to the valve. The repair cost me about 175 Euro and fixed all those symptoms, the stalling, jerking, and the check engine light. Could you share what's the mileage on your 4 Series? Also, have you noticed any unusual sounds from the engine bay or changes in fuel consumption? This info would help me give you more specific advice based on my experience. Before my repair, I also thought it was the air valve itself, but it was just the connection that needed fixing. It's a fairly common issue with these engines.

Thanks for sharing your experience! My car has 127111 KM on the clock, and I just had my regular service done last month. I haven't noticed any unusual sounds, but now that you mention it, I think my fuel consumption has slightly increased over the past few weeks. Seems like we might be dealing with the same issue. I'll definitely have the hose connections checked out first before replacing any major parts. Really helpful to know it might be something relatively simple and not too expensive to fix.

Oh hey again! Thanks for the extra details about your car. Based on the mileage you mentioned and the recent increase in fuel consumption, I'm even more convinced it's similar to what I dealt with. You know what's interesting, my fuel consumption also went up before I discovered the hose issue. I actually tracked it and was using about 10-15% more fuel than usual. After the fix, it went right back to normal. Since you just had your service last month, I'm a bit surprised they didn't catch this during the inspection. When I had my issue, it turned out the hose had developed a tiny crack that was barely visible, those BMW hoses can be tricky like that. The mechanic showed it to me after, and honestly, I would've never spotted it myself. Quick tip from my experience, when you take it in, ask them to specifically check the connection points where the hose meets the pump and valve. That's where mine was failing, and it's apparently a common wear point on these models. Just curious, does your engine run rough mainly when you first start it up? That was another telltale sign with mine that helped pinpoint the issue.

Thanks for the additional info! Yes, actually, the engine does run pretty rough during cold starts, especially in the morning. I didn't think much of it before, but now it makes total sense. Really appreciate the tip about asking them to check those specific connection points, that'll save me from potentially replacing parts I don't need to. I'll get it to the shop this week and have them look at exactly what you mentioned. It's such a relief knowing it might just be a hose issue rather than something major. You're right about the service, I'll definitely bring that up with them too, since they should've caught this during the inspection. Thanks again for all your help! Will update once I get it sorted.