Audi S3 Fuel Sensor Issue Causing Engine Problems

I had a very similar issue with my 2014 Audi S4, and can share some insight based on my experience with fuel injection problems. The symptoms you describe match exactly what I encountered, reduced power, stalling at idle, and the check engine light. In my case, the fuel pressure sensor was sending incorrect signals to the ECU, causing the fuel injection system to malfunction. The repair involved replacing the faulty rail pressure sensor, which resolved all symptoms. Total cost was 240 Euro including parts and labor. A few things to check before heading to the shop: Confirm fuel pressure readings using a diagnostic tool, Check for any visible damage to the fuel rail, Listen for unusual clicking sounds from the fuel injectors, Monitor fuel consumption changes To help provide more specific advice, could you share: Current mileage on your S3, When the symptoms first appeared, Whether the issues happen more during cold starts, If you notice any unusual sounds from the engine bay, What error codes your scanner showed The fuel rail pressure sensor is a common failure point in these engines, but its always good to rule out other potential causes. A proper diagnosis using manufacturer-specific diagnostic equipment will confirm if its just the sensor or if there are additional issues with the fuel injection system.

Current mileage is 160558 KM and last service was done 2 months ago. The symptoms first appeared about a week ago, mainly during cold starts. The error codes consistently point to fuel rail pressure sensor malfunction (P0193). No unusual sounds from the engine bay, but engine performance is definitely worse than normal. The engine stalling happens more frequently when the engine is cold. Once warmed up, it runs a bit smoother but still lacks power. Fuel consumption has increased by about 15% since these issues started. Your experience with the pressure sensor replacement gives me hope this might be a straightforward fix. Planning to take it to the shop next week.

Thanks for providing those details. The P0193 code and symptoms you describe are indeed very similar to what I experienced. After my sensor replacement on the S4, I noticed several key improvements that confirmed it was the right fix: The diesel engine performance returned to normal immediately after repair. The increased fuel consumption you mentioned also matches my situation, my consumption dropped back to normal levels once the rail pressure sensor was working correctly. One tip from my experience: Have them check the wiring harness connecting to the sensor while they are doing the repair. My mechanic found slight corrosion on the connector pins, which could have eventually caused similar fuel pressure sensor signal issues again. Since your car has similar mileage to what mine had when the issue occurred and the symptoms match (especially the cold start stalling), I am fairly confident you are dealing with the same rail pressure sensor failure. The repair should resolve both the stalling and power issues you are experiencing. Keep us posted on the repair outcome. It would be helpful to know if your fix costs are similar to the 240 Euro I paid for mine.

The error codes and symptoms you described match what I am experiencing perfectly. Based on the high mileage and similar check engine warnings, this really does sound like a straightforward fuel rail pressure sensor issue. Planning to book it in next week and will ask them to inspect the wiring harness too while they are working on it. The 240 Euro repair cost seems reasonable if it resolves both the engine stalling and power problems. Good to know that I am not looking at a major fuel system overhaul. Will definitely update once I get it fixed to confirm if replacing the pressure sensor gets everything back to normal. Really hoping this takes care of the cold start stalling and returns the fuel consumption to normal levels. Thanks for sharing your experience, it has given me a much clearer picture of what to expect with the repair.