MaxGosa88

Hi everyone, I’m having a strange issue with my BMW F20 116i 2012 (N13 engine) and I’m trying to figure out the cause. The problem appears only in a specific condition: After the car sits for about 4–6 hours (so not fully cold, but not warm either – kind of a semi-cold start). At startup, the engine revs higher as expected. As the RPM starts to drop, I can hear a brief wastegate rattle. Immediately after that, the RPM fluctuates slightly and settles around ~700 rpm, where I notice a small vibration/shake. After about 30–60 seconds or once I start driving, the engine becomes perfectly smooth with no vibration at all. Important notes: Cold starts (after overnight) are perfect Fully warm restarts are also perfect The issue only appears in this “semi-cold” condition Work already done: timing chain kit replaced injectors replaced ignition coils and spark plugs replaced MAF sensor replaced MAP sensor replaced lambda (O2) sensor replaced throttle body cleaned ECU adaptations reset No fault codes, no loss of power, and the car drives perfectly once stabilized. Has anyone experienced something similar or has any idea what could cause this behavior? Thanks!