T-Roc Fuel System Troubles: Stalling & Rough Idle Alert

Had a very similar issue with my 2016 VW Golf last winter. The symptoms were nearly identical, rough idle, engine misfire and sporadic stalling. After some initial troubleshooting, the check engine light helped narrow down the problem. As someone with moderate experience working on VWs, I first suspected fuel delivery problems, but it turned out to be much simpler. The workshop found a loose connection in the wiring harness going to the fuel pressure sensor. The plug had partially separated due to vibration over time. The fix was straightforward, they cleaned the connector contacts and properly secured the plug connection. Total cost was 95€ for diagnosis and repair. The fuel system was actually fine; the sensor was just getting intermittent power due to the bad connection. To help diagnose your specific case better, could you share: What error codes is your check engine light showing? Does the problem get worse when the engine is cold or warm? Have you noticed any changes in fuel consumption? Are there any other warning lights on the dashboard? The T-Roc shares many components with other VW models, so the fix might be similar. Getting those details would help determine if you are dealing with the same underlying issue.

Thanks for the detailed response. Yes, I should have mentioned the error code is P0171 (system too lean). The issue definitely gets worse when the engine is cold, especially during morning starts. The dashboard only shows the check engine light. Fuel economy has dropped from around 7L/100km to nearly 9L/100km over the past month. I might try having the wiring connections checked first since it worked in your case. Just had my 30000km service done two weeks ago, and they didnt spot anything unusual with the fuel system then. Interesting that you mention the harness issue, perhaps something got disturbed during the recent service. The rough idle is most noticeable at stoplights.

Thanks for providing those additional details. Based on the P0171 code and increased fuel consumption, this does sound like a typical fuel delivery issue, but not necessarily a bad fuel pressure sensor. After fixing the wiring harness on my Golf, I actually encountered a similar lean condition a few months later. The real culprit turned out to be carbon buildup on the fuel injectors reducing proper fuel atomization. This perfectly explains the cold-start issues and rough idle you mentioned. The repair involved having the fuel injectors professionally cleaned and the fuel pressure tested. Cleaning restored proper spray patterns and resolved all symptoms. Total cost was around 220€ including diagnostic time. Fuel economy returned to normal within two tanks. A few preventive tips that helped me avoid future issues: Using high-quality fuel with good detergent additives, Not consistently running the tank below 1/4 full, Regular fuel filter changes as part of maintenance Since you mentioned the recent service, definitely have them verify all fuel system connections were properly secured. But given the P0171 code and symptoms, dirty injectors seem more likely than just a sensor issue. A proper fuel system diagnosis will quickly pinpoint whether its injectors, pressure, or sensor-related.

Thanks everyone for the suggestions. After getting the car checked again, you were all spot on, it turned out to be a combination of issues. The fuel injectors were quite dirty and one fuel pump electrical connector was indeed loose, probably from the recent service work. The shop did a complete fuel system service including injector cleaning and secured all connections properly. The check engine light is now off and the rough idle is completely gone. Engine runs smooth even during cold starts. Fuel consumption is back to normal at around 7L/100km. Total repair cost was 285€ which included: Fuel system diagnosis, Injector cleaning service, Electrical connection repair, New fuel filter as preventive maintenance Really glad I asked here before replacing the fuel pressure sensor unnecessarily. Will definitely keep up with regular maintenance and use better quality fuel going forward. Thanks again for helping diagnose the real issues.