If the co is lean when hot, then consequently it will be leaner than intended when cold, this will cause issues as you have.
Mine starts 100% perfect and drives 100% perfect from cold within 1 second, can't even tell it's idling without looking at tacho, my iscv sometimes works mostly not, not worried though, still idles perfect when old, but then I'm not on L6.
A cold engine is vastly more arsey/sensitive when running of mixture differences.
Either get a full mapping job done or accept it's never going to be 100% of what it could be, otherwise there would be no point in mapping if there was no gain to be had from doings so, can make a world of difference even on std engines.
tabetha