BMW 1 Series Idle Issues: IAC Valve Mystery Revealed

I had nearly identical issues with my 2019 BMW 2 Series last winter. At first, I also thought it was the idle air control valve, but after taking it to the garage, they found heavy carbon buildup in the intake manifold, pretty common issue with direct injection engines. The symptoms matched yours exactly, unstable idle, unusual stalling, and that annoying check engine light. They had to do a thorough intake cleaning and replace a couple of sensors. It was quite a serious job that took them almost a full day, but the car has been running smoothly since then. Since your car's newer than mine was when this happened, I'd suggest getting the intake system checked first before replacing parts. If it is carbon buildup, catching it early prevents more expensive problems down the road. Hope this helps with your diagnosis.

Thanks for sharing your experience! That's really helpful because I've been worried about the repair costs. My symptoms sound exactly like what you described. Would you mind telling me how much the intake cleaning and sensor replacement set you back? Also, has everything stayed problem-free since the repair? I'd love to know if any other issues popped up afterward.

Hey there! Just wanted to follow up and share that I got my 2019 BMW 2 Series fixed last week. You were asking about costs, I ended up paying 425 € for the whole job. They found that it was indeed the intake system being heavily contaminated, just like I suspected when I first replied to you. The mechanic did a thorough cleaning of the intake and what a difference it made! That bad idle air control valve issue I mentioned before? Completely gone now. The car's running like a dream, smooth idle, no more stalling, and that pesky check engine light hasn't shown its face since. It's been about a week now, and I've had zero issues pop up. The engine feels much more responsive, and I'm actually saving a bit on fuel too, which is a nice bonus. Honestly, while the bill wasn't small, it was worth every cent to get the car running properly again. Just a heads up, if you do get it fixed, make sure they do a proper deep clean of the intake system. That seems to be the key to preventing these issues from coming back.

Just got back from the mechanic and wanted to update everyone. You were absolutely right about the carbon buildup! Took your advice and had them check the intake system first. Turned out my engine was pretty gunked up, even with relatively low mileage. The final bill came to around 400 for the cleaning and diagnostic work. Much better than what I was expecting to pay for a new idle air control valve! The mechanic showed me the before and after pictures of the intake, it was shocking to see how much carbon had accumulated. Been driving for a few days now and what a difference! The idle is steady, no more stalling, and that annoying check engine light is finally off. Engine feels more responsive too, almost like when I first got the car. Thanks again for steering me in the right direction. Really saved me from unnecessary parts replacement and probably a bigger headache down the road. Definitely learned my lesson about regular maintenance checks!