BMW X4 Diesel: Rough Running and Power Loss Issues

Hey there! I have some experience with cars, and I went through something very similar with my 2018 BMW X3 diesel last year. Those symptoms sound exactly like what I experienced, especially that annoying hissing and power issues. It turned out to be the intake manifold control switch that was acting up. I took it to my regular workshop, and they diagnosed it pretty quickly. The fix involved replacing the faulty switch and doing a system reset. Set me back about 465 Euro, but it sorted out all those issues, no more hissing, power's back to normal, and fuel consumption is much better now. Before we dig deeper though, could you share: What's your current mileage? Any warning lights on the dash? Did this start suddenly or gradually? This could help narrow things down, as these issues sometimes pop up differently in various BMW models, even the X4 and X3 can have slight variations.

Hey! Thanks for sharing your experience. My X4's currently at 167756 KM, and I haven't noticed any warning lights yet. The problem started gradually over the past couple of weeks. That price for the fix doesn't sound too bad, honestly. Just had my last service about 2 months ago, and everything was fine then. Your experience with the intake manifold control switch sounds spot-on with what I'm dealing with right now. Really helps to hear from someone who's been through the same thing. I'll probably get it checked out by my mechanic this week, just to be safe. Hopefully it's a straightforward fix like yours was!

Hey again! Thanks for getting back with those details. Yeah, that mileage is pretty similar to when mine started acting up (I was around 155000 KM). Since you mentioned it started gradually and there's no warning lights, it's even more likely to be the intake manifold control switch, exactly what I dealt with on my X3. Just a heads up though, when I first noticed these issues, I kept driving for a couple of weeks before getting it fixed, and it actually started getting worse pretty quickly. The hissing got louder and the jerking during acceleration became more pronounced. From my experience, it's definitely worth getting it sorted sooner rather than later. Also, since you mentioned your recent service, might be worth asking your mechanic why they didn't catch this during your service two months ago. Mine started shortly after a service too, and my mechanic explained that these switches can deteriorate pretty quickly once they start going bad. Let me know how it goes after you get it checked out. I'm curious if the fix will be as straightforward as mine was. When they fixed mine, it was like driving a completely different car afterward, smooth as butter!

Thanks so much for the detailed advice! You're absolutely right, I won't put off getting it checked any longer. I've actually noticed the hissing getting a bit louder just in the last few days, so your warning about it getting worse quickly really hits home. I'll call my mechanic first thing tomorrow morning to book it in. Good point about asking why they didn't catch it during the service. Though to be fair, the issues really only started becoming noticeable about three weeks ago, so maybe there weren't any red flags during the service. I'm really hoping it'll be a straightforward fix like yours was. The thought of getting back that smooth driving experience is definitely appealing! I'll keep you posted on what they find. Really appreciate you taking the time to share your experience, it's been super helpful in understanding what I might be dealing with. Fingers crossed it's just the intake manifold control switch and nothing more serious!