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hanswilson1

BMW 4 Jerks While Accelerating, CEL and Failed Emissions

Hey all! Having trouble with my 2019 BMW 4 (gas, 185,959 km) and need some advice. My check engine light is on, and the car's jerking during acceleration. It's been put into emergency mode, and I failed the emissions test recently. The mechanic I went to last time wasn't great, so I'm hesitant to go back. Has anyone dealt with similar symptoms? What was the diagnosis and how much did the repair cost? Looking for recommendations on what to check first or if anyone knows a trustworthy mechanic who's good with BMWs. Thanks in advance!

4 comment(s)

martinstorm3

Hey! I can relate. Had similar issues with my 2016 BMW 3 Series last month. The symptoms you're describing match what I experienced, jerking during acceleration and check engine light. It turned out to be a cracked exhaust manifold and a failed oxygen sensor in my case. The manifold crack was causing exhaust leaks, which messed with the sensor readings and made the engine run rough. Had to get both parts replaced. It was definitely a serious issue that needed immediate attention since it affects both performance and emissions. Left untreated, it could damage other components. Based on your symptoms, I'd say get the exhaust system and oxygen sensors checked first. The failed emissions test is a big clue, usually points to issues in those areas. A professional diagnostic scan would pinpoint the exact problem. Also, these issues often come together on BMWs around this mileage point, so worth checking the entire exhaust system while you're at it.

hanswilson1 (Author)

Thanks for sharing your experience, that really sounds similar to what I went through! Mind if I ask how much the repairs set you back in the end? Also curious if you've had any other issues pop up since getting it fixed? Always trying to stay ahead of potential problems with these cars.

martinstorm3

Hey again! Happy to give you an update. After seeing my mechanic, the uneven engine running was completely resolved. The total bill came to 265 € for fixing the exhaust leak, not too bad considering it was a BMW repair! Everything's been running smooth as silk since the fix. No more jerking during acceleration, and the engine's purring like a kitten now. The check engine light's stayed off too, which is always a good sign. I was actually worried it might be something more serious (and expensive!), but thankfully the exhaust leak was the main culprit. Once that was sorted, all the other symptoms cleared up. I've put about 3,000 km on it since the repair without any problems. Just a heads up though, while they had it up on the lift, my mechanic mentioned I might need new brake pads in the next few months. Always something with these cars, right? But at least the engine running issues are sorted! Let me know if you end up getting yours checked out. Curious to hear if it's the same problem.

hanswilson1 (Author)

Thanks everyone for the helpful responses! Just wanted to follow up and share what happened. I bit the bullet and took it to a different mechanic this time, what a difference! The guy really knew his stuff and took the time to explain everything. Turns out it was indeed an exhaust system issue, just like mentioned. Had a cracked manifold and two faulty sensors. The repair cost was a bit steeper than I expected, around 800 bucks total, but the car's running like new now. No more jerking, no check engine light, and I finally passed that emissions test! The mechanic did a thorough inspection while fixing the exhaust and mentioned my transmission fluid could use a change soon, but otherwise everything else looked good. Honestly, just relieved it wasn't something more serious with the engine itself. Again, thanks for pointing me in the right direction. Really helped me feel more confident about what to expect when I took it in. Here's hoping both our BMWs keep running smoothly for a while!

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