VW Nivus Stalling: Fuel Pressure Regulator Alert

I had a very similar issue with my 2021 VW T-Cross last month after changing the fuel filter. The symptoms matched exactly what you describe, rough idle, stalling issues, and the check engine light came on. The car felt like it was running on 3 cylinders during acceleration. After scanning, it showed a fuel pressure drop reading. The workshop found that the fuel filter housing wasnt properly sealed, causing air to enter the system. They had to purge the fuel lines and reseal the connection. Total cost was 45€ for diagnosis and fix. Before suggesting specific fixes, could you share: Has any recent work been done on the fuel system? Does the rough idle get worse when the engine is warm? Can you hear the fuel pump running when you turn the key to ON position? The symptoms could also point to a failing fuel pump or clogged injectors, but those issues typically show different behavior patterns. Once you share those details, I can provide more specific insights based on my experience.

Last service was at 20000km and everything seemed fine back then. The rough idle definitely gets worse when warm, and yes, I can hear the fuel pump running at key turn. No recent work done on the fuel system. When the engine misfire occurs, it feels more pronounced at higher RPMs. The pressure sensor readings from my OBD scanner show fluctuating values, suggesting an inconsistent fuel delivery pattern. I pulled codes P0171 and P0300 which point toward a lean condition and unusual misfires. Seems the fuel pressure regulator could be struggling to maintain proper pressure across operating conditions. Would you suggest getting the fuel system tested before replacing components? Fuel efficiency has also dropped noticeably over the past weeks, if that helps narrow things down.

Based on your codes and symptoms, its definitely worth testing the fuel system before replacing parts. My T-Cross showed similar behavior, P0171 code and degrading fuel efficiency before the full symptoms appeared. The fluctuating pressure readings from your OBD scanner strongly point to fuel delivery issues. When my pressure sensor readings were unstable, it turned out the fuel regulator was intermittently sticking, causing irregular pressure in the fuel rail. This matches your symptoms getting worse at higher RPMs. In my case, the fuel pressure test revealed the regulator was maintaining only about 65% of specified pressure under load. The rough idle and lean condition improved immediately after replacing the fuel regulator. Total repair cost was around 280€ including parts and labor. Since your symptoms worsen with engine temperature, definitely have them check the fuel pressure both cold and hot. This helped identify the issue in my case since the regulator would work fine cold but fail once heated up. Good move on checking those codes first, saves time and prevents replacing wrong parts. Keep monitoring fuel efficiency, as continuing to run with low fuel pressure could affect other components.

Thanks for all the insights. I'll take your advice and get the fuel pressure properly tested, especially since the symptoms match your experience so closely. You're right about checking both cold and hot conditions, it makes sense given how the problems worsen when warm. I scheduled an appointment for tomorrow to have them run a complete fuel system diagnostic. They mentioned they'll test the pressure regulator and inspect the entire fuel rail assembly. The shop quoted 75€ for the diagnostic test, which seems reasonable. The decreasing fuel efficiency combined with the engine misfire patterns and pressure sensor readings does point strongly toward the fuel regulator. I'll make sure they document the pressure readings for future reference. Really hoping its just the regulator and not a more extensive fuel system issue. Will update once I get the test results and know exactly what we're dealing with. Thanks again for helping narrow down the likely cause.