Audi A4 Rough Running & Fuel Pump Troubles Fixed

As someone with moderate experience working on cars, I had a very similar issue with my 2004 Audi A3 last year. The symptoms you describe match what I experienced, poor car performance, rough idling, and increased fuel consumption. Initially, I also suspected fuel pump failure, but in my case, the problem turned out to be much simpler. After diagnostic testing, the mechanic found that the fuel pump electrical connector had corroded, causing intermittent connection issues affecting gasoline delivery to the engine. The repair was straightforward, cleaning and replacing the damaged connector and wiring cost 95 Euro. This resolved all the symptoms, and the car ran perfectly afterward. No need to replace the entire fuel pump or fuel injector system. However, your situation might be different. To provide more specific guidance, could you share: Current mileage, When was the last fuel system maintenance done, Any unusual sounds when starting the car, Are there specific error codes stored The symptoms could indicate various fuel system issues, from a failing pump to clogged injectors. Proper diagnosis is crucial before replacing major components.

My last service was just 3 months ago at 85600 KM and everything was fine then. The engine stalling started happening suddenly last week. Thanks for mentioning the connector, I had a look but mine seems clean and properly connected. The error code I am getting is P0087 which points to low fuel rail pressure, making me think the fuel pump might really be the culprit in my case. When starting, there is a whining noise that was not there before. Would you suggest testing fuel pressure before committing to a full pump replacement? A local shop quoted 850 Euro for a complete fuel pump assembly replacement which seems quite steep. I want to be sure about the diagnosis before spending that much on car mechanics work.

Based on error code P0087 and the whining noise you describe, this does point more definitively toward a failing fuel pump in your case, unlike my simpler connector issue. The automotive diagnosis becomes clearer with these additional symptoms. The whining noise during startup is a classic indicator of fuel pump wear, and combined with the low fuel rail pressure code, suggests the pump is struggling to maintain proper pressure for engine operation. In my experience with auto repair on these models, fuel pressure testing is absolutely worth doing before any major work, it cost me about 60 Euro for the test when I had my issue. After fixing my connector issue, I actually ended up replacing my fuel pump about 6 months later when similar symptoms developed. The repair cost was around 780 Euro at that time, so 850 Euro seems in line with current prices for parts and labor. One suggestion based on my experience: while doing the fuel pump replacement, have them inspect the fuel filter as well. Sometimes debris from a failing pump can clog the filter, and replacing both components together can prevent future engine stalling issues. The fuel pressure test should give you confirmation, but given the error code and symptoms, prepare for a fuel pump replacement being necessary. The good news is that once replaced, these issues should be completely resolved.

Thanks for the detailed information. The whining noise and P0087 code definitely make me more confident it is the fuel pump. I will get the pressure test done first to confirm, 60 Euro sounds much better than jumping straight to the 850 Euro repair if it turns out to be something else affecting car performance. I appreciate the tip about checking the fuel filter too. Makes sense that a failing pump could send debris through the gasoline delivery system. I will ask them to inspect that during the pressure test and factor it into the repair if needed. Will book the pressure test for next week and update once I know more. The car is still running enough to get to the shop, though not very smoothly. Hoping this resolves all the engine stalling and rough running issues I have been experiencing.