VW Virtus Engine Misfire Signals Major Trouble

Had similar warning light and performance issues with my 2017 VW Jetta TSI. The check engine light flashing combined with rough idle often points to a misfire, which can be caused by various issues including faulty ignition coils or spark plugs. In my case, the poor performance and increased fuel consumption were caused by a loose connection in the knock sensor wiring harness. The connector had slight corrosion and wasnt making proper contact. The symptoms match what you describe, the engine protection mode kicks in when the knock sensor fails, causing the rough running and performance drop. This required removing the intake manifold to access the sensor area. While not a major repair, its important to address quickly since running without proper knock detection can damage the engine. The mechanic should perform a full diagnostic scan and check the knock sensor resistance values before replacing parts. Consider getting the spark plugs checked too since theyre due for replacement around 50000km. Bad plugs can create similar symptoms and trigger the knock sensor warnings. The repair itself needs proper diagnostic equipment and experienced hands to avoid damaging other components during disassembly. Would strongly recommend having a VW specialist check it rather than a general repair shop.

Thanks for the detailed explanation of your experience. The same happened to my Virtus last winter, engine knock and malfunction indicator lighting up. The mechanic found loose wiring at the knock sensor and corroded connectors, just like in your case. Curious how much the total repair cost was for you? For me, they changed the spark plugs while they were at it since they were already going in there. Just wondering if any other car problems or ignition timing issues showed up after getting it fixed?

Got good news to share after fixing the knock sensor issue on my Jetta. The mechanic charged 95€ to repair the faulty cable connection and clean the corroded connector. The auto repair was straightforward once they identified the exact problem. Since the repair, the engine knock completely disappeared and performance returned to normal. No ignition timing problems or other engine issues have shown up in the months following the fix. The check engine light hasnt come back either, which confirms it was definitely the knock sensor causing all those symptoms. It was smart of your mechanic to change the spark plugs while doing the repair. Fixing both issues at once probably saved you some labor costs compared to two separate visits. The poor performance and rough running completely cleared up after getting the proper sensor readings back. Having the repair done by a qualified shop that knew how to properly diagnose and fix the knock sensor was worth it. Running with a faulty sensor could have led to serious engine damage over time.

I finally got my car back from the mechanic yesterday! Just wanted to update everyone, total repair came to 280€, which included fixing the knock sensor wiring issue, replacing the spark plugs, and a full diagnostic scan. Labor was the biggest cost since they had to remove several parts to access the sensor area. The difference in performance is incredible. Fuel efficiency improved right away and that annoying rough idle is completely gone. No more malfunction indicator lights either. My mechanic explained that the poor ignition timing from the faulty knock sensor was causing the engine to run rich, which explained the high fuel consumption. Really glad I got it sorted quickly instead of driving around with the issue. The mechanic showed me the corroded connector they replaced, it was in pretty bad shape. No other problems have come up in the past week of driving, and the engine feels smoother than ever.