BMW XM Rough Idle Issues, Engine Mount Concerns?

Hi there! I've got some experience working on BMWs. Had a similar issue with my 2020 BMW X5 M. Initially thought it was the engine mount too, but turned out to be a faulty connector on one of the ignition coil cables. My local workshop diagnosed it after I brought it in with similar symptoms, rough idle, vibrations, and check engine light. Cost me 95 Euro to fix, mainly labor for testing and replacing the damaged cable connection. Before you assume it's the mount, what's the exact error code you're getting? Also, does the roughness change with RPM, or is it constant? This could help narrow down if we're dealing with the same issue. I've seen similar problems in other BMW M models too, like the M3. These performance engines are sensitive to electrical connections, so it's worth checking the simpler stuff before jumping to bigger repairs.

Thanks for the input! My current mileage is 151928 KM and I just had a service done last month. The error code I'm getting is P0171, and yeah, the vibrations definitely get worse when I rev the engine. The rough idle seems more noticeable in the morning when the engine's cold. I'll definitely have someone check those ignition coil connections, that's way better than dealing with engine mount issues! The dealership quoted me a crazy amount for diagnostics alone, so I might try your workshop suggestion first.

Hey again! Thanks for the extra details about your BMW XM. You know, after you mentioned the P0171 code and the symptoms getting worse with revving, I'm even more convinced it's similar to what I dealt with. The P0171 actually points to a lean fuel mixture, which makes sense with the rough idle and vibrations. In my case with my X5 M, I first thought it was just the ignition coil connector, but after digging deeper, we found a vacuum leak that was causing similar issues. The service cost me about 250 Euro total, more than just fixing the connector, but still way less than an engine mount replacement. Since you're noticing it more during cold starts, definitely get those vacuum lines checked. These performance BMWs can develop tiny cracks in the hoses that are hard to spot but cause all sorts of running issues. Mine started acting up around 145,000 KM, so we're in the same ballpark mileage-wise. Quick tip, if you're taking it to a workshop, ask them to smoke test the intake system. That's how they found my leak. Could save you some diagnostic time and money. Let me know what they find!

Thanks so much for the detailed follow-up! The vacuum leak theory makes a lot more sense now, especially since you mentioned the smoke test. I actually just called a few independent BMW specialists, and one of them mentioned exactly what you're talking about, they'd start with checking the vacuum lines and doing a smoke test. They quoted me 180 for diagnostics including the smoke test, which is way more reasonable than what the dealership wanted. It's really helpful to know that you had similar issues around the same mileage. I've scheduled an appointment for next week, and I'll definitely update the forum once I know what's causing it. Really appreciate you taking the time to share your experience, it's saved me from jumping to conclusions about the engine mount and probably saved me a bunch of money too! I'll keep you posted on what they find during the smoke test.