BMW 7 Series Rough Idle: Engine Mount or Something Else?

Hey there! I have some experience working on BMWs. Had a similar issue with my 2011 BMW 5 Series, and also worked a bit on my cousin's X3. When I faced those symptoms, I initially thought it was the engine mount too, but it turned out to be a loose connection in one of the ignition coil cables. The workshop spotted it during diagnosis, one of the plugs wasn't properly seated. Got it fixed for about 95 Euro, which included diagnostic time and fixing the connection. Before I can help more specifically with your 7 Series, could you share: Which engine variant you have? When did the shaking start? Are there any specific conditions when it shakes more (like when AC is on)? What error codes are you getting? This would help narrow down if it's the same issue I had or something else entirely.

Thanks for the detailed response! My car has the N63 4.4L engine, last serviced about 2 months ago at 100683 KM. The shaking started gradually over the past few weeks, and yeah, it definitely gets worse when the AC is running. The error codes I'm getting are P0171 and P0174, which from what I understand might be related to a lean fuel mixture. Haven't had any issues like this before. That's interesting about your ignition coil experience, might be worth checking those too. Starting to think it could be multiple things causing this.

Hey again! Thanks for providing those details about your N63. Those error codes definitely ring a bell, I had similar ones (P0171/P0174) on my 5 Series before the ignition coil issue was discovered. Given what you're describing, especially with the AC making it worse, I'm starting to think your issue might be more complex than what I initially dealt with. After getting my ignition coil fixed, I actually ended up having vacuum leaks that caused similar symptoms. The rubber hoses on these engines tend to get brittle over time, especially around the 100K mark where your car is at. In my case, I ended up replacing several vacuum lines and the valve cover gasket, which sorted out both the shaking and the lean codes. Total repair cost was quite a bit more than just the ignition coil fix, around 800 for parts and labor. But honestly, it was worth every penny because the car runs so much smoother now. Have you noticed any slight burning oil smell? That could help confirm if you're dealing with similar vacuum issues. Also, might be worth checking your MAF sensor, these engines can get pretty finnicky about air measurement, and a dirty MAF could definitely contribute to those lean codes. Let me know if you want more specific details about what exactly I had replaced, I kept all the receipts and notes from my repair journey!

Thanks so much for all this detailed information! Actually, now that you mention it, I have noticed a slight burning oil smell recently but didn't think much of it. This vacuum leak theory makes a lot of sense, especially given the mileage and symptoms. I really appreciate you sharing your repair experience, it's super helpful to know what I might be looking at cost-wise too. I'll definitely get those vacuum lines and valve cover gasket checked out along with the ignition coils. Better to address everything properly rather than just fixing one thing and having issues pop up again later. And yes, I'd love to see those repair details if you don't mind sharing them, always good to be informed before heading to the mechanic. Good call on the MAF sensor too, I'll add that to the list of things to check. You've really helped me narrow down the potential issues here. Will update you once I get it looked at!