Q5 Hybrid Stalls & Loses Power, Fuel System Alert

Had similar issues with my 2018 A6 hybrid. The symptoms matched exactly, rough idling, weak acceleration, and constant check engine warnings. The diagnosis revealed a failing high pressure fuel pump, which is a critical component in direct injection systems. This definitely requires professional attention, as the high pressure pump failure can lead to complete engine shutdown and potential damage to other fuel system components. The car sensors were showing erratic fuel pressure readings in my case. The repair involved replacing the entire high pressure pump assembly and recalibrating the fuel regulator system. The job took about 6-7 hours at the shop. After the fix, noticed immediate improvements in fuel economy and overall engine performance. Worth noting that driving with these symptoms can cause additional damage. If your fuel pressure is inconsistent, it could affect multiple engine components. Would recommend getting it checked soon, as this isnt a problem that typically resolves itself. My repair was covered under powertrain warranty, but its considered a major repair job due to the complexity of hybrid fuel systems.

Thanks for sharing your A6 experience. The symptoms match exactly what Im dealing with in my Q5. Your description of the high pressure fuel pump issue really helps narrow down what might be wrong. Since engine misfire and stalling issues can get expensive fast, Id like to know what repair costs looked like for you. Even though yours was under warranty, knowing the typical cost would help me prepare. Also wondering if youve had any recurring fuel system problems or if the fix has held up well? This car maintenance situation is stressing me out since my local automotive repair shop messed up my last service. Good to hear a success story with the same symptoms.

Just following up on your cost question. Since my initial post, I took my car to a certified shop and the diagnosis confirmed exactly what we suspected, the fuel volume regulator was faulty, causing those engine misfire issues. The total repair bill came to 1510 Euro for replacing the high pressure pump, which had completely failed. The fuel injection system is working perfectly now, and fuel economy has improved significantly. No recurring issues in the past months, so the fix seems solid. The engine runs smooth at idle and the power delivery is back to normal. These high pressure pump replacements are pretty reliable when done properly. The automotive repair was definitely worth the investment, considering how the failing pump could have caused more extensive engine damage. The car sensors are all showing normal readings now, and the check engine light hasnt come back on. Its running like new again. Given your similar symptoms, you might be looking at comparable repair costs. Its not cheap, but proper repair prevents bigger problems down the line.

Wanted to update everyone on how this turned out. Finally took my Q5 to a certified automotive repair center after getting the feedback here. The diagnostic confirmed a failing high pressure fuel pump causing the engine misfire issues. The car maintenance cost hit 1650 Euro total, slightly higher than expected but included a full fuel system cleaning. The repair took about 8 hours, and they found some additional wear on the fuel regulator that needed attention. Initial start-up was rough, but after the car sensors recalibrated, the engine runs perfectly now. No more stalling, full power restored, and the check engine light is finally off. Fuel economy actually improved quite a bit too. Really glad I didnt wait longer, mechanic showed me the old pump and it was definitely on its last legs. Could have caused serious engine damage if left unfixed. Definitely learned my lesson about addressing these issues quickly.