Audi A8 Fuel Pump Failure: Warning Signs & Solutions

I had a similar fuel system issue with my Audi A6 2016 gasoline model that showed nearly identical symptoms. With some experience in automotive diagnosis, I recognized these classic signs of fuel delivery problems. The rough running and stalling were particularly concerning, so I brought it to my regular workshop for proper car performance testing. They conducted a thorough fuel pressure test and electrical system check, which revealed the actual problem, a faulty wiring connection to the fuel pump. The repair was relatively straightforward. The mechanics found and fixed a damaged cable connection in the fuel pump wiring harness. Total cost was 95 Euro including diagnostics and repair. Much cheaper than replacing the entire fuel pump unit. For accurate troubleshooting of your A8, could you share: Current mileage, Any recent fuel system maintenance, Whether you notice these issues more when the tank is low, Specific error codes from the check engine light This information would help determine if your situation matches what I experienced with the wiring issue or if you might be dealing with a different fuel system component problem.

Last serviced at 104000 KM with current mileage at 109375 KM. Thanks for sharing your experience. The error code I got was P0171 and yes, the problems do get worse when the fuel tank drops below quarter full. Based on the diagnostic steps you mentioned, I will request a fuel pressure test to verify if its a pump failure or potentially just a wiring issue like in your case.

Thanks for providing those details. The P0171 code indicates a lean fuel mixture, which aligns perfectly with the symptoms we both experienced. After seeing your mileage and the error code, I strongly suspect your issue could be identical to what I encountered with my A6. When my fuel pump wiring failed, I also noticed more frequent engine stalling and worse performance with a low tank, exactly like your symptoms. The lean mixture code combined with increased fuel consumption often points to inconsistent gasoline delivery rather than a complete pump failure. The fuel pressure test is definitely the right next step. In my case, the test revealed fluctuating pressure readings that helped pinpoint the wiring issue. While a failing pump would show consistently low pressure, intermittent readings usually indicate electrical problems. Since auto repair costs vary significantly between pump replacement and wiring fixes, its worth having a proper automotive diagnosis done first. In my situation, the electrical repair solved all symptoms, including the rough engine running and check engine light. Keep us updated on what the pressure test reveals. Based on the matching symptoms and error code, I wouldnt be surprised if you find a similar wiring problem.

Thanks all for the helpful responses. After taking it to my mechanic yesterday for the fuel pressure test, they confirmed it was indeed an electrical connection issue similar to what experienced. The test showed fluctuating pressure readings just as described. The repair cost came to 120 Euro for diagnostics and fixing the damaged wiring harness. After the auto repair, the car performance has returned to normal, no more stalling, rough running, or excessive fuel consumption. The check engine light is now off and the engine idles smoothly. Really glad I asked here before assuming it needed a complete fuel pump replacement. The automotive diagnosis process helped identify the true issue and saved me from an unnecessary expensive repair. For anyone else experiencing similar symptoms, definitely get the fuel pressure test done before replacing parts.