BMW X4 Rough Idle Mystery: Engine Mount or Something More?

I dealt with similar symptoms in my 2016 BMW X3 last year. The rough idle and shaking turned out to be a faulty ignition coil and spark plug connection. Thought it was engine mounts too, but my mechanic found the actual issue after diagnosing the fault codes. The fix involved replacing two ignition coils and all spark plugs since they were worn out anyway. Not a super expensive repair, but definitely something you want to address quickly to prevent any damage to the catalytic converter. The whole job took about 2 hours at the shop. Been running smoothly since then, no more shaking or rough idle issues. My advice would be to get those fault codes read properly first, it'll save you from replacing parts unnecessarily.

Hey, thanks for sharing that info about your X3! That's really helpful since I've been worried about my X4. Just curious, do you remember roughly how much you ended up paying for those coils and plugs? Also, has everything stayed running smoothly since the repair, or have you noticed any other issues pop up? My symptoms sound pretty much identical to what you described.

Hey there! Happy to give you an update. Actually, after I wrote that first reply, I ended up taking my X3 back to the mechanic because the initial diagnosis wasn't quite right. Turns out it wasn't the ignition coils after all, it was a defective engine mount that was causing all that shaking. The mechanic found a bad cable connection related to the component too. Got it all fixed up and it cost me 95€ for the cable/plug connection work. Much cheaper than I thought it would be! Since getting that sorted, my X3's been running like a dream, no more shaking or rough idle issues at all. It's been really solid. Looking at your symptoms now, they sound exactly like what I dealt with. Would definitely recommend getting those engine mounts checked out first. It's funny how similar issues can point to different causes, right? That's why proper diagnosis is so important. Let me know how you get on with yours!

I really appreciate you following up with that extra info! After your message, I bit the bullet and took my X4 to a new mechanic yesterday. You won't believe it, it was actually a combination of problems. Had a worn engine mount AND a loose cable connection, just like your case! The mechanic was super honest and showed me exactly what was wrong. Total bill came to about €120 for parts and labor, which was way less than I expected. They even showed me the old mount, it was completely shot. Car's running beautifully now, no more shaking or rough idle. Feels like a totally different vehicle! Really glad I didn't ignore those symptoms. Thanks again for sharing your experience, it gave me the push I needed to get it checked out properly. Sometimes changing mechanics turns out to be the right call!