Rough Idle Points to Failing Alfa V6 Engine Mount

As someone with some hands-on experience working on Alfas, I had a similar issue with my 2003 Alfa 156 3.2 V6. The symptoms you describe match what I experienced, rough idle, vibrations, and warning lights. Initially thought it was a failed mount too, but after inspection, the mechanic found the issue was actually related to a faulty wiring connection near the transmission mount area. The cable harness had worn through due to contact with the mounting bracket, causing intermittent electrical issues. The repair cost 95 Euro and involved securing new cable connections and protective wrapping. This fixed both the rough idle and eliminated the vibrations completely. Before jumping to replace any engine mount or transmission mount, have a mechanic check the wiring around the mounting areas. Mount wear can cause similar symptoms, but electrical issues can mimic mount failure pretty convincingly. Could you share: Any trouble codes from the check engine light? Does the vibration change with engine temperature? Are the vibrations worse at specific RPMs? Have you noticed any fluid leaks around the mount areas? This info would help determine if your issue matches what I experienced or if you truly have mount wear to address.

Just had my annual service at 72474 KM and can confirm similar symptoms appeared shortly after. Getting the wiring checked is a good suggestion, but in my case it turned out to be a defective engine mount. The repair showed severe mount wear on the passenger side, which explained the increasing vibrations. The trouble codes pointed to misfire-related issues, but replacing the mount resolved everything. The warning light disappeared and the rough idle smoothed out completely. The failed mount was causing the engine to shift position under load, affecting multiple systems. Total repair came to 280 Euro including labor. A proper inspection of all mounting points is worth doing since transmission mount issues often follow once one mount fails.

Thanks for confirming your repair outcome. The 280 Euro cost actually lines up with what others have reported for mount replacements on these Alfas. The relationship between mount wear and misfire codes is pretty common, a failed mount allows enough engine movement to affect sensor readings and timing. Your mileage threshold matches a known pattern with these V6s. The passenger side mounting bracket typically shows wear first, followed by transmission mount issues if left unchecked. Good call getting it fixed promptly. Since you mentioned your annual service, its worth noting that regular inspection of motor mounts became a standard check on these models after 2004 due to the number of failures reported. The rubber compound used tends to deteriorate faster than expected, particularly under the V6s additional weight and torque. For preventive maintenance, checking the remaining mounts every 20000km is recommended. A failed mount on one side increases stress on the others, often leading to cascading failures. Best practice is inspecting all mounting points when replacing any single mount. Keep monitoring for any returning vibrations. If they start creeping back, get the transmission mount checked next as its typically the second point to show wear on these engines.

Just got the latest vibration issues checked after noticing the rough running. Turns out both you and my mechanic were spot on about checking all mounting points. Had a complete inspection done and found the transmission mount starting to show early signs of wear. The mounting bracket on the engine side was still solid, but getting that rubber mount replaced now makes sense given what you mentioned about preventive maintenance. Going to schedule that repair next month, better 190 Euro now than waiting for a complete mount failure. Will definitely keep an eye on vibration issues going forward. Having dealt with the earlier mount wear problem taught me how these things can cascade. The tip about 20000km checks is helpful since my usage fits right into that interval. Makes total sense about the V6 putting extra stress on these components. The rough idle I experienced initially was a clear warning sign of mount issues. Good to know about the 2004 service bulletin too, explains why my mechanic was so quick to check the mounts during inspection.