Noticed that when its very cold -10c and below my car struggles to idle. Lights inside flicker, headlights flicker, ventilation, climate controls, cluster. Whole car basically flickers RPMs aswell they drop to zero sometimes while driving too when breaking. Cleaned IACV and checked my battery while car was off and idle and in rev and everything checks out. So good alternator and battery i THINK. Any idea what the cause could be? Battery when its excessively cold? Vacuum leak?? I have no idea.