VW Scirocco Stalling: Bad Fuel vs. Fuel System Issues

Having low experience with car repairs but dealt with a similar issue on my VW Golf 2015 last year. The symptoms were nearly identical, rough idle, stalling, and check engine light. Initially suspected fuel contamination since the problems started after refueling, but the actual culprit was a faulty connection to the fuel injection sensor. The poor connection was causing incorrect readings in the combustion chamber, leading to an improper fuel mixture. Took it to a workshop where they diagnosed and fixed the cable connection issue for 95€. The repair resolved both the stalling and check engine light. Fuel economy returned to normal after the fix. Before suggesting specific solutions, it would help to know: Current mileage on your Scirocco, When did these symptoms first appear, Does the problem get worse when the engine is cold or warm, Have you noticed any changes in fuel consumption Getting the error code read would definitely help pinpoint the exact issue. Bad fuel could cause similar symptoms, but the persistent check engine light suggests it might be a sensor or connection problem in the fuel system.

Latest service was 2 months ago at 16000km, so I will provide more details as requested. The symptoms started about 3 days ago, roughly 200km after filling up at that new station. The engine runs especially rough when cold, taking longer than usual to stabilize. The problem seems less noticeable once warmed up. Fuel consumption has increased noticeably, getting about 15% worse than normal. The engine knock is most prominent during initial startup and when idling at traffic lights. I am concerned about potential fuel contamination since the timing matches with using that new fuel station. Will get the error codes read tomorrow, but wanted to check if anyone else encountered these specific symptoms with their fuel system before visiting the workshop. The engine has been reliable before this, with no previous fuel filter changes or similar issues since purchase.

Thanks for providing those details. Our situations sound very similar, my Golf had the exact symptoms after using a questionable fuel station. However, in my case, a fuel system cleaning and new fuel filter resolved the issue completely. After that experience, I learned rough idle and increased fuel consumption can definitely point to fuel contamination issues. The symptoms being worse when cold is particularly telling, that matches what I experienced before getting it fixed. Since your issues started right after using that new station, I would strongly suspect contaminated fuel is causing problems with your fuel system components. The increased fuel consumption and cold start issues are classic signs. Suggestions based on my experience: Get those error codes read first, Consider adding a quality fuel additive to help clean the system, Have the fuel filter inspected and possibly replaced, Fill up with premium fuel for the next few tanks The total repair in my case included: New fuel filter: 65€, Fuel system cleaning service: 120€, Fuel additive treatment: 25€ If these steps dont help, then checking the fuel injection sensor connections would be the next logical step, like in my previous repair. But the timing and symptoms really point toward fuel contamination in your case. Looking forward to hearing what the error codes reveal, that should help confirm if were dealing with a fuel system issue or something else.

Thank you everyone for the input. I will follow up with the diagnostic results tomorrow. To summarize what I learned: The symptoms, rough idle, stalling, increased fuel consumption and cold start issues, appear consistent with fuel contamination in the fuel system. This makes sense given the timing after using that new station. I will get the error codes read first thing tomorrow and ask them to inspect the fuel filter. Based on the advice, I will also: Add a quality fuel system cleaner, Switch to premium fuel for the next few tanks, Have them check for any sensor connection issues if the basic fixes dont resolve it The estimated costs shared for fuel filter replacement, system cleaning and additives give me a good baseline for what to expect. Will avoid that new station until I confirm whether contaminated fuel was indeed the root cause. Appreciate all the practical suggestions. Will update once I have the diagnostic results and know more about what is actually causing the fuel mixture problems.