VW Lupo Fuel Sensor Issues Causing Rough Running

I encountered a very similar issue with my 2000 VW Polo diesel last year. I have some experience working on diesel engines, but with complex fuel delivery systems, I prefer leaving it to professionals. The symptoms you describe match exactly what I experienced, rough idle, check engine light, and jerky acceleration. Initially, I also thought it was the fuel pressure sensor, but after inspection, my mechanic found that the issue was actually a loose connection in the wiring harness leading to the fuel injector system. The fix involved cleaning the connectors and securing the wiring properly. Total cost was 95€ for diagnostics and repair. After this fix, the check engine light turned off and the fuel economy improved significantly. Before jumping to conclusions about the fuel pressure sensor, it would help to know: Have you noticed any changes in fuel consumption? Are there any specific error codes showing up? Does the rough idle happen more when the engine is cold or warm? What maintenance has been done on the fuel system recently? These details would help determine if your issue is similar to what I experienced or if it might be something else in the fuel delivery system.

Thank you for sharing your experience. After reviewing my service records, my last maintenance was done at 85000km where they performed a standard service including fuel filter replacement. Since then, fuel consumption has increased by about 2L/100km and I get error code P0087 which indicates low fuel rail pressure. The engine stalling happens more frequently when the engine is cold, especially during the first 5 minutes of operation. The fuel pump has never been replaced in my ownership period. Would be helpful to know if replacing just the sensor fixed your issues completely or if additional repairs were needed?

Thanks for providing those details, they actually reveal a different situation than what I experienced with my VW Polo. While my initial problem was indeed resolved with the wiring fix, your error code P0087 and the increased fuel consumption strongly suggest a fuel system pressure issue. After my wiring repair, I did end up having to replace both the fuel pressure sensor and the fuel pump about 2 months later when similar symptoms returned. The engine misfire and rough idle came back worse than before, especially during cold starts. The complete repair included: New fuel pressure sensor (180€), Fuel pump replacement (395€), System diagnostic and calibration (120€) This comprehensive fix finally solved all issues: No more engine stalling, Fuel consumption returned to normal, Check engine light stayed off, Smooth acceleration without jerking Given your specific error code and symptoms, especially the cold start issues, you might want to skip the sensor-only replacement I tried first and go straight for the complete fuel system overhaul. It would likely save money in the long run.

Based on your experience with the similar VW and error code P0087, I think I should start with a complete fuel system inspection rather than just replacing the sensor. The cold start issues and increased fuel consumption definitely point toward more than just a sensor problem. I will take it to my mechanic and request a thorough check of both the fuel pump and pressure sensor. Looking at the costs you shared, I should budget around 700€ for a complete fix if both components need replacement. This makes more sense than spending 180€ on just the sensor only to potentially need the pump replaced shortly after. Good to know the repair solved all your issues completely. The symptoms match exactly what I am experiencing with the rough idle and stalling during cold starts. Will schedule the inspection this week and make sure they check the entire fuel delivery system. Thanks for helping me avoid the trial-and-error approach with individual parts.