Audi A7 Fuel Rail Sensor Issues Causing Stalls

I had almost the exact same issue with my 2013 Audi A6 last summer. As someone with moderate experience working on cars, I initially thought it might be a simple fuel pressure issue. The symptoms matched yours exactly, rough idle, stalling, lack of power, and that annoying check engine light. The diagnostic scan also pointed to the fuel rail pressure sensor signal being inconsistent. Took it to a workshop where they confirmed the sensor was defective and needed replacement. The repair process was straightforward: Full diagnostic check, Replacement of the faulty pressure sensor, System recalibration, Test drive to confirm proper fuel injection operation Total cost was 240 Euro including parts and labor. Since the fix, the engine runs perfectly with no stalling or power issues. To help with more specific details about your case, could you share: Engine size and type, Current mileage, When did these symptoms first appear, Any recent maintenance or repairs, Does the stalling happen more when the engine is cold or warm This information would help determine if your case is similar and might need the same fix.

Thanks for the detailed response. My A7 has 31391 KM on the clock and just had its regular service last month. After reading your experience, it does sound very similar. The fuel injection system seems especially problematic when the engine is cold. Interesting that the pressure sensor was the culprit in your case, gives me a good starting point. The check engine light has been persistent for about two weeks now. Will book it in for a proper diagnostic check based on your feedback about the rail pressure issue.

Thanks for the additional details. After my successful sensor replacement, I monitored the fuel rail pressure closely for a few months to ensure everything was working correctly. The cold-start symptoms you describe are exactly what I experienced, the faulty pressure sensor signal causes the system to deliver incorrect fuel amounts during cold operation. The fuel pressure regulation tends to be more critical during cold starts when the rail needs precise control. My mechanic explained that when the sensor starts failing, it often shows up first in cold conditions before becoming a constant problem. Since your A7 has relatively low mileage and recent service, this strengthens the case for a sensor issue rather than a more complex fuel rail problem. In my experience, the pressure sensor tends to fail electronically rather than mechanically, which matches the pattern of intermittent signal issues you described. One thing to note, after my repair, the workshop recommended checking the fuel pressure readings periodically through the diagnostic system, especially during the colder months. This helps catch any sensor signal degradation early before it leads to stalling issues again.

Good news, I think I can narrow down the issue with my diesel engine based on your feedback. Since my cold-start problems match what you experienced, I feel more confident its related to the rail pressure sensor signal. The fact that your fix cost 240 Euro for parts and labor seems reasonable. The timing matches too, my stalling issues started showing up about two weeks ago, right after some cold mornings. Makes sense that the faulty sensor would cause problems with fuel delivery during cold starts before becoming a constant issue. Will schedule the diagnostic check tomorrow and specifically mention the fuel rail pressure sensor symptoms you described. At least now I know what questions to ask and roughly what to expect cost-wise. Thanks for sharing your experience and repair details, definitely helped point me in the right direction for fixing these engine stalling problems.