VW Fox Diesel Stalling Issue Points to Fuel Regulator

Having dealt with similar issues on my VW Polo 2008 diesel, I can share some relevant experience. After working on several car projects, I have moderate experience with fuel system issues. The symptoms you describe match what I encountered, poor power delivery, stalling, and check engine warnings. However, in my case, it turned out to be a failing high pressure fuel pump rather than the fuel regulator. The workshop diagnosed this through proper diagnostic tests of the fuel injection system. The repair involved: Complete system diagnostic scan, Removal and replacement of the high pressure pump, Fuel system cleaning and pressure testing, Reset of all related car sensors, Test drives to confirm fuel economy and performance Total cost was 1510€ including parts and labor. The repair completely resolved the stalling and power issues. Before jumping to conclusions about the fuel regulator, it would help to know: Current mileage on your Fox, When was the last fuel system service, Are you getting any specific error codes, Have you noticed any unusual fuel consumption patterns, Does the problem occur more during cold starts This information would help determine if your issue matches what I experienced or if it might be something different.

Thanks for the information about the high pressure pump. My last service was done 2 months ago and nothing unusual was detected during car maintenance. The stalling mostly happens during warm engine operation, not cold starts. I checked my fuel efficiency over the last month and noticed it dropped about 15%. The engine management light shows error code P0087 which points to low fuel rail pressure. Your repair experience is valuable since the symptoms match, especially the stalling and power loss. Will get the fuel injection system properly checked based on your feedback rather than assuming it is just the regulator. Better to have car sensors and the entire fuel delivery system tested to pinpoint the exact issue.

Based on error code P0087 and the symptoms you describe, it definitely mirrors the fuel pressure issues I faced. Since your car maintenance was recent but didnt catch this, the problem likely developed quickly, which is exactly what happened with my Polo. The fuel efficiency drop is a clear indicator of fuel injection system problems. When my high pressure pump started failing, I saw similar decreases in fuel economy before the more severe symptoms appeared. A quick tip from my repair experience: when they test the fuel system, make sure they check the pressure at different RPM ranges. My issue was particularly noticeable at specific engine speeds, which helped pinpoint the failing component. The workshop should run comprehensive fuel system diagnostics including: Fuel pressure testing under load, Electrical testing of fuel pump circuits, Inspection of fuel lines for restrictions, Testing of associated car sensors For the interim, try to maintain the fuel tank above quarter full, running low on fuel can strain an already struggling fuel pump. The repair restored my cars performance completely and brought fuel consumption back to normal levels. Will be interested to hear what they find during diagnostics. The fuel injection system is complex, but proper diagnosis will save time and money in the long run.

Thanks again for sharing those details about the fuel system diagnostic process. Based on your experience, I will make sure to request comprehensive testing at different RPM ranges. This issue has gotten more frequent, yesterday the car stalled twice during normal driving. The car sensors and fuel efficiency data are definitely pointing toward fuel delivery problems. Just checked my mileage log and I am now at 185000km. Given the age and mileage, a failing high pressure pump makes sense as the potential culprit affecting fuel injection performance. I will schedule an appointment next week for a full fuel system inspection. Will make sure they do the electrical testing and pressure checks you mentioned during car maintenance. Avoiding low fuel levels in the meantime is also good advice to prevent additional strain. Hopefully diagnosing the exact cause will lead to the right fix like in your case. The repair cost seems reasonable considering the comprehensive work involved. Will update once I get the results from the workshop.