Tiguan Diesel's Rough Idle Points to Misfiring Issues

Had a similar issue with my 2017 VW Touareg TDI last year. The symptoms matched exactly what you describe, rough idle, significant power loss, and intermittent check engine light. The diagnosis revealed a cylinder misfire caused by a faulty fuel injector. The combustion misfire was particularly noticeable during cold starts and when accelerating from low speeds. After running diagnostics, it turned out one injector was not delivering fuel properly, causing irregular combustion and engine misfiring. The repair involved replacing the problematic fuel injector and running a complete fuel system cleaning. This was definitely a serious issue that needed immediate attention, as continuing to drive with a defective injector risks damaging other engine components. The repair process itself was straightforward for an experienced mechanic with the right diagnostic tools. However, fuel injectors need precise calibration after installation, which requires specialized equipment. The job took about 4 hours at the shop. Make sure to get proper diagnostics done to confirm which injector is causing the issue. Rough idle and power loss symptoms can worsen quickly if left unaddressed.

Thanks for sharing your experience with the Touareg fuel injector issue. It sounds extremely similar to what my Tiguan is going through. I checked with my local mechanic and they also suspect a faulty injector causing the engine misfiring and rough idle. They mentioned needing specialized diagnostic equipment to pinpoint the exact problem. Would you mind sharing how much the repair ended up costing you? Also curious if youve had any related issues since getting it fixed, did the fuel system cleaning help prevent future problems?

Just got back to confirm that the repair completely resolved those engine misfiring issues in my Touareg. The combustion misfire symptoms disappeared right after fixing the faulty injection valve, and the rough idle problem never returned. Total cost came to 515€ for the injector replacement, including parts and labor. The fuel system cleaning they performed as part of the service seems to have helped maintain smooth operation. No check engine light or performance issues in the 8 months since the repair. The engine runs perfectly now, no more jerking or power loss during acceleration. The specialized diagnostic equipment they used was crucial in identifying exactly which injector was causing the problem. Getting it fixed promptly likely prevented additional engine damage, so it was worth every cent. Just make sure your mechanic has experience with VW injection systems for the best results.

Thanks for the input. I finally got my Tiguan fixed last week and wanted to share my experience. After taking it to the shop, their diagnostics confirmed a faulty fuel injector was causing the cylinder misfire and rough idle issues. The repair process took about 5 hours since they also did a thorough fuel system cleaning. Total cost was 480€ which included the new injector, labor, and cleaning service. The throttle response is now perfect and the engine runs smoothly without any jerking or power loss. The mechanic showed me the old injector which had significant carbon buildup affecting its spray pattern. They recommended doing fuel system cleaning every 30000km to prevent similar issues. Really glad I got this sorted before it caused more engine damage. The check engine light has stayed off and the car feels like new again. Thanks for helping me understand what I was dealing with, made the repair process much less stressful knowing what to expect.