BMW M3 Stalling & Sluggish: Fuel Rail Mystery?

I had similar issues with my 2020 BMW M4. The symptoms you're describing match exactly what I experienced, rough idle, hesitation during acceleration, and the dreaded check engine light. The pressure sensor in the fuel rail was indeed the culprit in my case. Had it diagnosed at the dealership, and the scan showed the fuel pressure wasn't being regulated properly. It's not a catastrophic problem, but it definitely needs fixing because it can lead to worse issues if left unchecked. The repair involved replacing the high-pressure fuel sensor and recalibrating the engine management system. Got it sorted in about half a day. Since the fix, the car has been running smooth as silk, no more stalling or rough idle issues. If you're uncertain about mechanics, the dealership is a safe bet for this kind of diagnosis, especially with a newer M3. They have the right diagnostic tools and experience with these performance models.

Thanks for sharing your experience! That's really helpful and matches what I'm seeing with my car. Glad to hear you got it sorted out. Do you remember roughly how much you ended up paying for the fix? And has everything been running smoothly since then, or have you noticed any other quirks pop up?

Hey there! Yeah, I got the rail pressure sensor fixed and it cost me 240 €, actually not too bad considering how much some BMW repairs can set you back. Since getting it sorted, my M4's been running like a dream, honestly, night and day difference from before. No more of that annoying rough idle or stalling, and the acceleration is back to being properly crisp like it should be. The engine warning light hasn't shown its face again either. It's been about six months now and I haven't had a single issue pop up. The car feels just as responsive and smooth as when I first got it. Looking back, I'm just glad I didn't wait too long to get it fixed, these things can snowball if you leave them too long. Trust me, if you're seeing the same symptoms, getting that sensor sorted will make a massive difference. You'll feel it as soon as you start the engine.

Thanks everyone for the advice! Just wanted to give a quick update, I bit the bullet and took my M3 to get checked out. The mechanic confirmed it was indeed the fuel rail pressure sensor causing all the trouble. Fixed it up yesterday and wow, what a difference! The idle is perfectly smooth now, no more stalling, and the car's got its punch back when I hit the gas. Bill came to around 280 for parts and labor, honestly not as painful as I was expecting for a BMW repair. Found a great mechanic too, super knowledgeable guy who took the time to explain everything. He even showed me the old sensor and pointed out exactly what was wrong with it. Really glad I didn't put this off any longer. Car's running like new again! Think I'll stick with this mechanic from now on. Feels good to have found someone who knows what they're doing with these performance models.