VW T-Roc Intake Manifold Troubles & Diagnostic Tips

I had nearly identical issues with my 2021 VW Tiguan diesel last summer. As someone who does basic maintenance but leaves major repairs to professionals, the symptoms you describe match my experience exactly, especially the engine misfire and rough running. The manifold pressure readings were all over the place, causing the engine management system to throw multiple fault codes. After thorough diagnostics, my trusted workshop confirmed a gasket leak in the intake manifold due to heat damage, which is apparently not uncommon in these engines. The repair involved: Complete manifold removal and inspection, Replacement of damaged gaskets and seals, Cleaning of the intake ports, System pressure testing, Diagnostic fault code clearing Total cost was 1180€ including parts and labor. Since the repair, the car runs perfectly with no check engine lights or performance issues. To better assist with your case, could you share: Current mileage on your T-Roc, When the symptoms first appeared, Whether the issues get worse when the engine is hot, Any diagnostic codes you retrieved This information would help determine if your car manifold has similar damage patterns to what I experienced.

Last service was done at 62000km, so I think it could be related. My symptoms started about 2 weeks ago and definitely get worse when the engine is hot. The manifold sensor readings are unstable according to the live data from my OBD scanner. The error codes I got are P0106 and P0171, which apparently point to intake manifold pressure issues and a lean fuel mixture. I notice the rough running is most pronounced during cold starts and when accelerating from low speeds. Worth noting these issues appeared quite suddenly after a particularly long highway drive. The gasket leak diagnosis makes a lot of sense given the symptoms and timing. I will have the workshop check the manifold pressure and intake system thoroughly during the upcoming appointment.

Your symptoms and error codes match my experience exactly, especially the P0106 manifold pressure sensor code and lean mixture readings. The sudden onset after highway driving is also very similar to what happened with my Tiguan. The unstable manifold pressure readings from your OBD scanner strongly suggest a gasket failure, just like mine. High temperature highway driving often reveals these issues as the heat stress affects the seals. Since fixing my intake manifold, the engine performance returned to normal with no more check engine warnings or rough running. Make sure your workshop does a complete pressure test of the intake system, in my case they initially missed a small crack that was causing intermittent manifold pressure fluctuations. My repair also included replacing all related seals while the manifold was off, which only added about 90€ to the total but prevented future leaks. Given your mileage is close to when my issues occurred, this preventive approach might be worth considering. One tip: have them check the intake ports for carbon buildup while the manifold is removed. A thorough cleaning definitely improved throttle response in my case and could help prevent future problems.

Thanks for sharing those additional details about your Tiguan repair experience. The correlation between highway driving and sudden symptoms matches my situation perfectly. Looking at the error codes and diagnostic data, I am now quite confident we are dealing with the same intake manifold gasket failure. I have scheduled a workshop appointment for next week and will specifically request: Complete intake system pressure testing, Inspection of all gaskets and seals, Check for any vacuum leaks, Carbon buildup examination while manifold is off, Full system diagnostics to rule out sensor issues Your suggestion about preventively replacing all related seals makes good sense given the mileage. The extra 90€ seems worth it to avoid future engine performance problems. I will discuss this option with the workshop. I appreciate the detailed repair breakdown including costs, helps set realistic expectations. Will update once I get the final diagnosis and repair completed. Hoping for similar positive results in resolving these engine misfire and rough running issues.