Audi Q7 Diesel Manifold Issues Cause Multiple Failures

As someone with some hands-on experience with VAG diesel engines, I dealt with a very similar issue on my 2017 Audi Q5 diesel. The symptoms you describe match what I experienced, rough idle, engine misfire, and reduced power output. The check engine light came on first, followed by the jerky acceleration about a week later. After scanning, it showed multiple codes related to air intake and manifold pressure problems. The workshop confirmed a vacuum leak caused by a scorched intake manifold, which was affecting the engine performance significantly. The complete repair included: Replacement of the intake manifold assembly, New gaskets and seals, System pressure testing, ECU recalibration Total cost was 1180 Euro including parts and labor. The repair prevented what could have been more serious engine damage if left unchecked. To provide more specific advice about your Q7, could you share: Current mileage, Specific error codes from the diagnostic scan, Whether there are any unusual sounds during cold starts, If you notice excessive black smoke from the exhaust, Service history, especially regarding intake system maintenance These details would help determine if your issue matches what I experienced and whether youre likely looking at a similar repair path.

Thanks for the detailed response. My odometer shows 194059 KM and the last service was done 4 months ago. The symptoms match exactly what you described with the air intake and manifold pressure issues. I also noticed the check engine light appeared shortly before the jerky acceleration started. The cold start noise has become more pronounced recently, especially in the morning. During the last service they cleaned the intake manifold but did not replace any components. My mechanic mentioned possible vacuum leaks in the intake system but wanted to try the cleaning first. Based on your experience, it seems I might need the complete replacement after all. The repair cost you mentioned helps with budgeting. Did the new manifold fix all issues immediately or did you need additional adjustments after installation?

Based on your mileage and symptoms, it definitely mirrors my experience with the manifold sensor and vacuum leak issues. After my complete manifold replacement, the engine performance improved immediately, the misfire and rough running cleared up within the first few drives. The cleaning they attempted during your service was a good first step, but when these symptoms persist, it often indicates deeper issues with the manifold assembly itself. In my case, the manifold gasket leak had caused some carbon buildup that cleaning alone couldn't fix. One thing I noticed after the repair: the engine idle smoothed out completely, and that strong exhaust smell disappeared. The ECU recalibration was crucial, it took about 100km of driving for the system to fully adapt to the new manifold and optimize performance. A word of caution from my experience, continuing to drive with these symptoms risks additional engine wear. The air intake issues can lead to improper fuel mixture and potentially more expensive repairs down the line. Would you be able to share the specific error codes? This would help confirm if youre dealing with the same root cause I encountered.

The mileage reading and detailed symptoms you shared definitely help confirm my suspicions. I have noted down the error codes you mentioned and will share them with my mechanic. After the manifold cleaning failed to resolve my issues, I feel more confident now that a full replacement might be needed. The progression of symptoms matches perfectly, from initial check engine warnings to the current rough running condition. Your point about the ECU adaptation period after repair is particularly helpful. I will plan accordingly and expect some adjustment time once the work is done. The total repair cost of 1180 Euro seems reasonable considering the comprehensive work required. Given that my cold start noise has worsened and the vacuum leak symptoms persist, I will schedule the repair soon to prevent any additional engine damage. It is encouraging to hear that the fix resolved all your issues and restored proper engine performance. Would you mind sharing how long your manifold repair took to complete? I need to plan for alternate transportation while the car is in the shop.