Audi A3 Fuel Sensor Causing Dangerous Stalls at Idle

I had almost the exact same fuel sensor problem with my 2006 Audi A4 a few months ago. Being somewhat experienced with car electronics and fuel system issues, I initially thought it was more serious. The car dashboard was showing similar symptoms, the check engine light and the fuel gauge started acting erratically. My car was also stalling at idle, which was quite concerning. After taking it to the workshop, they did a complete diagnostic scan of the fuel tank system. Turned out it was just a blown fuse connected to the fuel sensor circuit. The total repair was 52 Euro, mostly diagnostic fees since the fuse replacement itself was straightforward. Before spending money on replacing the entire fuel sensor, you should have the fuse box checked. These sensors are usually quite reliable, and often the issue lies in the surrounding electrical components. Could you share: Have you noticed any issues with your fuel gauge readings? Does the problem occur more frequently with a full or near-empty tank? What specific error code is showing up? Did you make any recent repairs or modifications to the fuel system? This information would help determine if your issue matches what I experienced or if its something different in the fuel delivery system.

Latest service was just done at 64926 KM, but sadly the faulty sensor issue persists. Thanks for sharing your experience. Our symptoms do sound similar. My fuel gauge has been showing inconsistent readings lately. The problem seems worse when the tank is less than quarter full. The error code is P0172, suggesting a rich fuel mixture. No recent modifications or repairs to the fuel system were done before this started. The workshop quoted 350 Euro for a complete fuel sensor replacement, which seems steep compared to your fuse fix. Will definitely have them check the fuse box and car electronics first based on your feedback.

Thanks for the additional details. Based on the P0172 code and inconsistent fuel gauge readings, this actually seems different from my fuse issue. The rich fuel mixture code points toward a fuel system problem beyond just the level sensor. Got similar symptoms in my A4 about a year after the fuse incident, but that time it turned out to be a faulty sensor combo, both the fuel level sensor and oxygen sensor were failing. The rich mixture reading is often tied to the oxygen sensor giving bad data to the engine computer. In my case, the complete fix included: Replacing the oxygen sensor (180 Euro), New fuel level sensor (290 Euro), System diagnostic and reset (60 Euro) The total was higher than your quote, but it solved both the stalling and gauge issues completely. Given your symptoms and error code, you might want to have them check both sensors. A faulty oxygen sensor can cause the rich mixture while a bad level sensor explains the gauge problems. Worth mentioning, after the repair, make sure they clear all stored error codes and verify the fuel trim values are back to normal. This confirms the fix addressed the root cause in the fuel system. Would suggest getting a second opinion on that 350 Euro quote, as prices for genuine sensor parts can vary significantly between suppliers.

Thanks everyone for the helpful insights. After getting a second opinion, it looks like I might be facing a dual sensor issue too. The new workshop confirmed both the faulty sensor in the fuel tank and potential oxygen sensor problems. Their diagnostic showed the same P0172 code, but they did more detailed fuel system testing. Got a quote of 320 Euro for both sensors plus labor, which seems more reasonable than the first estimate. Going ahead with the repair next week. Will update on whether replacing both the fuel sensor and oxygen sensor fixes the stalling and gauge problems completely. Really hoping this resolves the rich fuel mixture issues too. Makes sense now why a simple fuse check wouldnt have solved it, the error codes and symptoms clearly point to actual sensor faults in the fuel system. Appreciate all the feedback that helped narrow down the real problem.