Sometimes I need to crank for a while until it fires up and sometimes not. Read somewhere that if it starts instantly when pushing the throttle pedal a little then it could be the iacv. That works. Sine they are amazingly cheap I thought of ordering one for testing that theory.
Do they need some kind of process where they have to be calibrated with diagnostic software or is it a simple plug and play procedure ?

Plug and play, just don't turn the ignition on with it plugged in but not mounted.

Perfect, thanks.