Rough-Running A3 Hybrid Points to Intake Valve Issues

The symptoms described match what I experienced with a 2019 Audi A4 Hybrid. The rough running and check engine light pointed to a vacuum leak where the hoses connect to the throttle body. The root cause was deteriorated vacuum hoses that created inconsistent manifold pressure and disrupted the air supply. This caused engine stalling at idle and rough running under acceleration. The throttle body wasn't receiving accurate airflow data, making the engine run rich. These symptoms are often misdiagnosed. The fix required replacing several vacuum hoses and resealing connections at the intake manifold. While not a complex repair, leaving it unaddressed can lead to more severe engine performance issues and potential damage to other components. A qualified technician should perform a smoke test to properly diagnose vacuum leaks. The repair is relatively straightforward once correctly identified, but requires attention to detail when reconnecting all vacuum lines to restore proper manifold pressure. This is a known issue in several VAG hybrid models from that generation. Having it properly diagnosed and repaired early prevents more extensive engine problems down the line.

I had exactly these idle problems with my A3 last winter. The check engine light came on and engine was running terribly. After weeks of frustration, my mechanic found vacuum leaks in multiple spots around the air valve assembly. My case sounds very similar to what you described. The vacuum hoses were cracked and caused irregular air pressure readings. Once replaced, the engine ran perfectly again. Could you share what you ended up paying for the repair? Also curious if you have experienced any related issues since getting it fixed?

Glad to report my air valve issue was completely resolved. The repair cost came to 175 Euro for fixing a faulty hose connection between the pump and valve. Since having it properly diagnosed and fixed, the check engine light has stayed off and the engine runs smoothly. The vacuum leak was causing erratic air intake readings, which made the throttle body compensate incorrectly. Getting the right diagnosis made all the difference. The earlier repairs at other shops missed the root cause, but once the correct issue was identified, the fix was straightforward. It has been 8 months since the repair, and I have not experienced any related problems. The idle is stable and acceleration is smooth. This seems to be a common issue with these models, but once properly addressed, it typically doesnt return. The key was finding a technician who recognized the specific symptoms and knew where to look for vacuum leaks in the intake system. The proper repair has proven to be a lasting solution.

Thanks for trusting me with my Audi A3. After reading about similar experiences, I took it to a new mechanic who specializes in European cars. The diagnosis confirmed multiple vacuum leaks around the air valve assembly, just as suspected. The total repair came to 320 Euro, which included replacing three damaged vacuum hoses and resealing the manifold pressure connections. The mechanic found cracks in the original hoses that were causing inconsistent air supply readings. The check engine light cleared immediately after repair, and the rough running completely disappeared. It has been running perfectly for the past three months with no issues. The idle is stable, and the acceleration is smooth again. The solution was much simpler than previous shops had suggested. Finding a mechanic who understood these specific vacuum systems made all the difference. For anyone else facing similar symptoms, definitely have the intake system pressure tested first before attempting more complex repairs.