VW Up Sensor Issues Causing Performance Drop

I dealt with a very similar issue on my 2016 VW Polo last year, so I have some experience with this type of problem. The symptoms you describe match exactly what I experienced, poor engine performance, increased fuel consumption, and constant check engine light. Initially, I also thought it was just a faulty manifold pressure sensor, but my mechanic found a significant vacuum leak in the intake system. The automotive sensor readings were actually correct, they were detecting the leak rather than being faulty themselves. After a thorough diagnosis, they found cracks in the intake manifold gasket which was causing incorrect manifold pressure readings and affecting overall engine performance. The complete repair, including diagnostic time and parts, cost 235€. The fix restored proper engine performance and fuel economy back to normal levels. Before jumping to conclusions about sensor failure, it would be helpful to know: Have you scanned for error codes? Are there any unusual sounds, especially whistling noises? When did the symptoms first appear, suddenly or gradually? Has any recent maintenance been performed on the intake system? With this information, I could provide more specific insights based on my experience with a very similar system.

Just had my 49086km service last month and noticed similar symptoms right after. Got it scanned and error code P0106 came up. Based on the diagnostic results and your experience, I am convinced I should check for vacuum leaks before rushing into sensor replacement. The car engine has been running more roughly since the service, creating a subtle whistling sound at higher RPMs. When the manifold pressure readings are off, it does make sense to inspect the entire intake system first. Will have my mechanic do a proper vacuum leak test. If the intake manifold or gaskets are damaged, replacing just the sensor would be a waste of money. Thanks for highlighting how the automotive sensor readings can actually be accurate while pointing to a different underlying issue.

Thanks for the follow-up. Your symptoms definitely mirror my experience, especially that whistling sound at higher RPMs. That was a telltale sign of the vacuum leak in my case too. The timing of your symptoms appearing right after the service is particularly interesting. During routine maintenance, technicians often need to disconnect various intake components, and sometimes gaskets or seals can get damaged during reassembly. My intake manifold gasket issue actually developed after a routine service as well. The P0106 code combined with the whistling noise strongly suggests an intake system leak rather than sensor failure. When my mechanic performed the smoke test, it clearly revealed the leak around the manifold gasket area. The engine performance improved immediately after fixing the actual leak. The proper vacuum leak test is absolutely the right approach here. In my case, what initially seemed like a straightforward sensor replacement turned into a more comprehensive but necessary intake manifold repair. The total diagnostic and repair process took about 3 hours, but it completely resolved the engine performance issues and restored normal fuel consumption. Let us know what the leak test reveals. Based on the matching symptoms and error code, I suspect youll find a similar intake system issue rather than a faulty sensor.

Thanks for the detailed response. I did the vacuum leak test today, and you were absolutely right. The mechanic found a significant leak where the intake manifold connects to the throttle body. The gasket was damaged, likely during my recent service when they accessed that area. The repair cost was 280€ including labor and parts. The manifold sensor readings are now back to normal since the intake system is properly sealed. Engine performance has completely recovered and the whistling noise is gone. No more check engine light either. Really glad I checked for vacuum leaks first instead of just replacing sensors blindly. This forum saved me from unnecessarily replacing functioning car sensors. Will definitely pay more attention to strange noises and performance changes after future services, since that seems to be when these intake manifold issues can develop. Thanks again for sharing your experience, the similarities between our cases helped pinpoint the actual problem quickly and saved both time and money.