A7 Diesel Stalling: Fuel Regulator Failure Alert

I experienced almost identical issues with my 2019 A6 diesel last year. As someone with moderate experience in car maintenance, I initially thought it was just a sensor problem, but it turned out to be more serious. The symptoms matched yours exactly, engine misfires, power loss, and that frustrating check engine light. After trying basic troubleshooting like checking fuel quality and replacing the fuel filter, I had to take it to a workshop. The diagnostic tests revealed a defective high pressure pump, which was causing irregular fuel delivery and affecting engine performance. The repair involved: Complete fuel system diagnostic scan, Replacement of the high pressure pump, System bleeding and recalibration, New fuel sensors installation Total cost was 1510 Euro and took about 2 days to complete. The fuel efficiency improved significantly after the repair, and all power delivery issues were resolved. Before suggesting specific solutions, could you provide: Current mileage, Fuel type normally used, Any recent car maintenance performed, When did these symptoms first appear, Any unusual sounds from the engine bay This information would help determine if your issue is similar to what I experienced with the high pressure pump failure.

Thanks for sharing your experience. My A7 has 182829 KM and had its last major service just 3 months ago. The automotive repair shop did a full inspection then and everything checked out fine. The fuel injection symptoms started about 2 weeks ago, getting progressively worse. No unusual sounds, but the engine misfire happens more frequently during cold starts. I exclusively use premium diesel and always fill up at major stations. Your repair situation sounds similar to mine given the matching symptoms. The cost seems reasonable considering the work involved. I will have the high pressure pump checked as a priority when I take it in. The check engine light patterns definitely suggest a fuel delivery issue rather than just a sensor malfunction. Would you recommend getting the fuel lines flushed as part of the diagnostic process? My fuel efficiency has dropped about 20% since these issues started.

Thanks for the additional details. Given your vehicle history and symptoms, this does sound very similar to my experience, especially with the cold start issues and declining fuel efficiency. In my case, getting the fuel lines flushed was actually a crucial diagnostic step. The workshop detected metal particles in the fuel system during the flush, which confirmed the high pressure pump was deteriorating. The flush helped prevent these particles from causing additional damage to other components. The progressive nature of your symptoms matches my situation perfectly. The rough idling and engine misfire patterns started mild but became more pronounced over about 3 weeks. Your 20% drop in fuel economy is also consistent with what I experienced, I was seeing around 25% worse efficiency before the repair. A few observations based on my repair experience: The cold start issues were resolved immediately after the pump replacement, Fuel efficiency returned to normal within 2 tanks of fuel, The automotive repair shop should check the fuel pressure sensor while they are at it, Getting the entire fuel system inspected is worth the extra diagnostic time One tip: request a fuel pressure test before and after repair. This helped confirm the fix was successful in my case and provided baseline readings for future reference.

I appreciate the detailed response and recommendations. The similarities between our cases are quite striking. After checking my service records, I noticed the fuel pressure readings from my last service were slightly below normal, which adds weight to the high pressure pump theory. I will schedule the repair next week and make sure to request both the fuel system flush and the pressure tests you mentioned. The check engine light patterns combined with the cold start issues and fuel economy drop really point to a systemic fuel delivery problem rather than an isolated sensor issue. My main concern was the potential repair cost, but 1510 Euro seems reasonable for such a comprehensive fix. The fuel injection system is critical, and skimping on repairs could lead to bigger problems. I will update the forum once I get the diagnostic results and repair completed. One last question, did your workshop suggest any preventive maintenance steps to avoid similar fuel regulator issues in the future? My declining fuel efficiency is becoming a real problem, especially with current fuel prices.