The fact that yours starts with idle valve and doesn't with it disconnected shows the valve to be functional, it will start without it but for cold starts you need to compensate by using throttle for a moment though. Can you keep the car going by using throttle, if so it shows the base idle is to low.

Do the revs drop then it stops? Normally they jam open and you have the opposite a high idle and that's why you need to clean and lube them.

Martin