VW Polo Diesel: Power Loss Points to Fuel Filter Issue

Had a similar issue with my 2017 VW Golf diesel last winter. The symptoms you describe match exactly what I experienced, power loss, rough idle and increased fuel consumption. After some initial troubleshooting, I took it to my regular workshop where I have some experience with the mechanics. The diagnosis revealed a loose plug connection at the fuel filter heater, which was causing intermittent operation. The connection had corroded over time, leading to poor contact. The repair involved cleaning the contacts and securing the connection properly. Total cost was 95€ including diagnostic time. Since the fix, the engine runs smoothly again with normal fuel consumption and no more power loss during cold starts. The rough idle completely disappeared. To better assist with your specific case, could you share: Current mileage on your Polo, When was the last fuel filter replacement done, Are there any other warning lights on the dash, Does the engine stalling occur more frequently in wet conditions These symptoms can sometimes also point to a clogged fuel filter or fuel system issues, so having this information would help narrow down the cause.

My Polo has 79943km on the clock and the last major service was completed 6 months ago, including a fuel filter replacement. Since your response seems promising, I will check the fuel filter heater connection first. The rough idle occurs regardless of weather conditions, and there are no additional warning lights aside from the engine warning light that triggered the stored fault code. The engine stalling happens mostly during the initial cold start phase. After warming up, the symptoms improve slightly but the power loss remains noticeable throughout the drive. Thanks for sharing your experience, as it gives me a good starting point to investigate.

Thanks for the additional details about your Polo. Your mileage and maintenance history actually make me lean away from my initial fuel filter heater theory, since you had a recent filter replacement. After hearing about the cold start issues and consistent power loss, I suspect you might be dealing with a fuel pressure regulator problem instead. When I faced similar symptoms in my Golf after ruling out the filter heater, it turned out the pressure regulator was failing, causing inconsistent fuel delivery to the engine. The fuel system loses proper pressure regulation, leading to poor cold start performance and ongoing power loss even after warm-up. A faulty pressure regulator typically costs around 150€ to replace, but it completely resolved my fuel efficiency issues and restored normal engine response. Before heading to the workshop, you might want to listen for any unusual clicking or ticking sounds from the fuel system area while idling. This was a telltale sign in my case. Also, check if you notice any fuel smell, as a failing pressure regulator can sometimes cause slight fuel seepage. Would you mind running the engine for about 5 minutes at idle and checking if you notice any of these symptoms? This could help confirm if we are looking at the same issue.

Since the warning light is active and the issues persist despite the recent fuel filter replacement, I will try checking for those clicking sounds you mentioned. Just ran the engine for about 5 minutes as suggested, and I do hear a faint but noticeable ticking noise coming from the fuel system area. No fuel smell detected though. Given that my symptoms match yours and the recent maintenance rules out simpler causes, I think you might be right about the pressure regulator. The persistent power loss even after warm-up and cold start problems align perfectly with what you described. The repair cost also seems reasonable if it resolves all these issues. I will schedule an appointment with my workshop and have them specifically check the fuel pressure regulator. The diesel engine problems have been quite frustrating, especially during morning commutes when the cold start issues are most noticeable. Thanks for helping narrow down the likely cause, this definitely gives me a more informed starting point for the repair.