Audi A3 Hybrid Knocking Issue Signals Engine Trouble

As someone with moderate experience working on hybrids, I dealt with a very similar issue on my 2020 Audi A4 Hybrid. The symptoms you describe strongly suggest deposits in the combustion chamber, which can affect engine knock sensor readings and cause irregular ignition timing. My car showed identical symptoms, power loss, jerking during acceleration, and blue smoke. The knock sensor was registering abnormal combustion events, which caused the engine management to adjust timing conservatively. The workshop performed: Combustion chamber cleaning, Knock sensor function test, Complete ignition timing adjustment, Engine tuning recalibration Total repair cost was 425 Euro including diagnostics. After the service, performance returned to normal and the smoke disappeared. To provide more specific advice for your case, could you share: Current mileage, Service history, Type of fuel regularly used, When symptoms first appeared, Any recent maintenance work The fix process might differ based on these details, as engine tuning requirements can vary between specific models and production years.

Last service was done at 25000 KM and currently showing 28502 KM on the odometer. Thanks for the detailed analysis. I checked my electronic log and noticed the piston slap noise started a few weeks after hearing metallic knocking sounds at low RPMs. Will get the cylinder heads inspected based on your input. Just wondering if anyone else experienced major component replacements for similar symptoms.

Thanks for providing those details. The combination of metallic knocking sounds followed by piston slap is concerning, as this can indicate more serious issues than just carbon deposits in my experience with my A4. After my initial diagnosis and repair attempt, the problems actually returned within a few weeks. Further investigation revealed pre-ignition damage to the cylinder heads, which explained the recurring knock sensor warnings and power loss issues. The complete repair ended up requiring: Full cylinder heads replacement, New knock sensors, Updated engine tuning calibration, Detonation monitoring system check The total cost jumped to 3200 Euro, but this resolved all symptoms permanently. The engine tuning parameters now stay stable and the detonation issues are completely gone. Given your relatively low mileage, I would strongly recommend getting a comprehensive cylinder head inspection done before any major component wear occurs. Early detection of pre-ignition damage can prevent more extensive engine repairs later. Would be helpful to know if your check engine light shows any specific knock sensor or detonation-related codes to better pinpoint the issue.

Based on that check engine code P0325 showing up, I suspect there could indeed be more serious issues developing. Since my mileage is still relatively low at 28502 KM, this is quite concerning. The metallic sound definitely got worse over time before the piston slap started, which matches your experience with cylinder head problems. Your repair experience is really useful to know about, especially since the initial fixes didnt fully solve it. The fact that you needed full cylinder head replacement makes me think I should push for a thorough inspection rather than just basic diagnostics. The knock sensor warnings combined with combustion chamber symptoms seem to point toward similar pre-ignition damage. Will schedule a comprehensive inspection focusing on the cylinder heads and knock sensor system. The 3200 Euro repair cost is steep but still better than risking major engine damage. Really hoping I can catch any issues early before more detonation problems develop. Will update once I get the full diagnosis results.