VW Fox Diesel Misfiring and Power Loss During Acceleration

As a VW Polo TDI (2010) owner, I faced nearly identical symptoms last year. The check engine light combined with rough running and power loss pointed to a cylinder misfire, which was traced to a faulty fuel injector. The diagnosis revealed carbon buildup inside the injector, preventing proper fuel atomization. This caused incomplete combustion and engine misfiring, especially noticeable during acceleration. The problem progressively worsened over time. The repair required: Complete injector removal and testing, Professional cleaning of all injectors, Replacement of one defective injector, ECU reset after installation This was a serious issue requiring immediate attention, as continuing to drive risked further engine damage and increased fuel consumption. A certified diesel specialist confirmed that injector problems are common in these engines, particularly after 80000km. Key indicators it was injector-related: Rough idle, Power loss during acceleration, Uneven engine performance, Check engine light activation, Black exhaust smoke Recommend having a diagnostic scan performed first to confirm the cylinder misfire codes before any repairs begin. This will help identify which cylinder is affected and narrow down the problem area.

Thanks for your detailed response. Really spot on as the symptoms match exactly what I experienced. My VW has been running great since the fix, though I still periodically check for any signs of engine misfiring just to be safe. Quick follow up, what were the repair costs in your case? Also curious if youve had any spark plug or fuel injector issues since the initial repair? My local shop suggested a full injector service might be needed soon as preventive maintenance, but Id like to compare notes before committing.

Thanks for asking about the costs. In my case, the repair was completed about 8 months ago and cost 515€ for replacing the defective fuel injector. The combustion misfire issues were completely resolved after this fix, and the engine has been running smoothly since then. I havent experienced any fuel injector problems since the repair. The rough idle and power loss symptoms disappeared completely. As for preventive maintenance, I opted for a basic injector cleaning service at the 100000km mark, but that was just routine care rather than addressing any specific issues. A full injector service as preventive maintenance makes sense, especially considering our engines are of similar age. These TDI engines are known to develop carbon deposits over time, which can affect fuel atomization and potentially lead to rough running conditions if left unchecked. Just keep monitoring for any unusual engine behavior or return of the check engine light. Based on my experience, proper injector maintenance has helped maintain consistent engine performance and prevent future misfiring issues.

I took my VW to a certified diesel specialist after reading the helpful advice here. The diagnosis confirmed exactly what was suspected, a faulty fuel injector causing cylinder misfire issues. The repair cost came to 490€, which included cleaning all injectors and replacing the problematic one. The rough idle and combustion misfire symptoms disappeared completely after the fix. The engine now runs smoothly without any jerking during acceleration. I also had them perform a thorough inspection of the ignition coils while they were at it, just to be thorough. The mechanic showed me the carbon buildup they cleaned out, which explained the power loss I was experiencing. They recommended regular injector cleaning every 40000km to prevent similar issues. Really glad I addressed this when I did, apparently continuing to drive with faulty injectors could have caused more expensive engine damage. My VW has been running perfectly for the past 2 months. I keep an eye on the engine performance but havent seen any warning lights or experienced any further misfiring problems. Definitely worth getting it properly diagnosed and fixed by specialists who know these engines.