VW Sharan: Jerky Acceleration + Engine Misfire Fix Needed

I had a very similar issue with my 2013 VW Touran diesel last winter. I have some experience working on cars, mainly basic maintenance and troubleshooting. The symptoms you describe match exactly what I experienced, engine misfire, jerking during acceleration, and rough idle when cold. After checking several possibilities including spark plugs and fuel injectors, my mechanic found a significant leak in the exhaust system, which was causing incorrect readings from the oxygen sensor. The total repair came to 265€, which included replacing a corroded section of the exhaust and the faulty oxygen sensor. After the fix, the engine check light went off and the car runs smoothly again. To help diagnose your specific case more accurately, could you share: Current mileage on your Sharan, When was the last time you had a major service, Are there any other warning lights on the dashboard, Does the problem get better once the engine warms up, Have you noticed any unusual exhaust smoke or smells A proper diagnosis is important since engine misfire symptoms can have multiple causes. Getting it fixed soon is crucial to prevent potential damage to other engine components.

Thanks for sharing your experience. My Sharan has 82089km on the odometer, with the last major service completed just 3 months ago. The problem does improve slightly when the engine warms up, but the jerking during acceleration remains noticeable. The error codes consistently point to cylinder misfires. No other warning lights are present on the dashboard besides the check engine light. After reading about similar cases, I suspect the fuel injectors might need cleaning or replacement, but I want to be sure before spending money on repairs. The rough idle is particularly concerning, as it makes the whole car vibrate when stationary. Has anyone else tracked down a similar issue to faulty injectors? The diesel engine complicates things compared to typical ignition coil problems in petrol engines.

Based on your described symptoms and the error codes, your suspicion about the fuel injectors might be right. When I faced this issue with my Sharan, the rough idle and misfires were indeed traced to clogged injectors, not the exhaust system as initially thought. After the injector cleaning service, my mechanic discovered one injector was beyond saving and needed replacement. Once fixed, the engine misfire warnings cleared up completely. The timing of your issue matches my experience, these problems often show up around 80000-90000km even with regular maintenance. The fuel pump can also contribute to similar symptoms, but in most cases, its the injectors causing the trouble. A fuel system cleaning service costs around 180€, while a complete injector replacement runs about 350€ per injector. However, getting this fixed is essential since continued misfires can damage other engine components. Quick tip: Using a quality diesel fuel additive every few tanks can help prevent injector deposits from building up. This preventive measure has kept my car running smoothly since the repair. Have you noticed if the problem gets worse after refueling or when the fuel tank is low?

The timing belt seems fine since it was checked during the recent service. I'll investigate the fuel injector suggestion, it makes sense given the symptoms. Just checked, the problem definitely gets worse when the tank is below quarter full. I contacted my regular mechanic and booked the car in for next week. He mentioned testing both the fuel pump and injectors to identify the exact cause. The quote for diagnostic work is 120€, which seems reasonable. I noticed black smoke from the exhaust this morning, which apparently is another sign pointing to injector problems. Really hoping it won't need all injectors replaced, as that would be quite expensive. Will update once I get the actual diagnosis. Thanks for the detailed suggestions about the fuel system. It helped narrow down the likely causes instead of replacing parts out of nowhere. The crankshaft sensor seems less likely now given the correlation with fuel level and black smoke.