Q5 Engine Mount Issues Causing Rough Idle

Having worked on cars as a hobby mechanic, I encountered a similar issue with my 2021 Q7. The vibration issues and rough idling were nearly identical to what you describe. The workshop diagnosed a faulty wiring connection at the mounting bracket, which was causing erratic sensor readings and engine management issues. While I initially suspected a complete mount failure, it turned out the engine mount itself was fine. The repair involved fixing a damaged cable connection near the motor mount assembly, costing 95 Euro for parts and labor. The symptoms improved immediately after the repair. No more vibrations at idle and the engine management light cleared up completely. Before suggesting specific solutions, it would help to know: Current mileage on your Q5, When did the symptoms first appear, Are the vibrations worse at specific RPM ranges, Have you noticed any unusual sounds along with the vibrations, Which specific error codes were stored This information would help determine if your issue matches what I experienced or points to a different underlying cause.

Thanks for the input. My Q5 is at 85674 KM and had its last scheduled service 3 months ago. The symptoms started about 2 weeks ago, getting progressively worse. The vibrations are most noticeable at idle and between 1500-2000 RPM. There is also a distinct knocking sound when accelerating from a stop. The stored codes point to multiple misfires, but given the physical symptoms, I am still suspecting a transmission mount or motor mount issue. The vibrations feel more mechanical than electrical, especially with that knocking sound. Will definitely have the wiring checked though, since your experience shows it could be a simpler fix than a complete mount failure.

Based on the additional symptoms you described, especially the knocking sound during acceleration, this seems different from my wiring issue on the Q7. Engine mount wear often manifests exactly as you describe, with progressive vibration issues and knocking sounds during load changes. The combination of misfiring codes with mechanical symptoms suggests two possible scenarios from my experience: 1. A severely worn engine mount allowing excessive engine movement, which can stress connected components including wiring harnesses and fuel system parts, leading to the misfire codes. 2. The transmission mount could be failing, particularly given the specific RPM range where you notice the vibrations. When my Q7 had a transmission mount failure last year, it showed similar symptoms before being diagnosed. Given your mileage and the progressive nature of the symptoms, I would strongly suggest having both the engine and transmission mounts inspected. My mount replacement ended up costing 450 Euro including labor, but prevented potential damage to other components. The knocking sound during acceleration is a classic sign of mount failure that I did not experience with my wiring issue, making me more convinced your case points toward actual mount defects rather than electrical problems.

Based on all the excellent insights shared and considering my initial concerns, I am now quite convinced the issue points toward actual failed mounts rather than just wiring. The knocking sound during acceleration seems to be the key differentiator, matching exactly what others have described for motor mount failures. The combination of my symptoms, rough idling, vibrations between 1500-2000 RPM, knocking during acceleration, and the misfire codes, all align with what was mentioned about worn engine mounts affecting multiple systems. Having both the transmission mount and engine mount checked makes complete sense given how the symptoms have progressed over these past weeks. The estimated repair cost of 450 Euro for mount replacement is helpful for budgeting. While I would have preferred a simple wiring fix, preparing for a more substantial repair seems prudent given all these classic signs of mount wear. Will book the workshop visit tomorrow and have them thoroughly inspect the mounting system. Really appreciate the detailed comparison of symptoms that helped narrow down the likely cause.