^in my vitz the cold engine light was blue, when it went out i knew i could drive normally (Y)
as for auto choke, if you notice, older cars rpms used to be very high when the choke was on, bt modern cars only rev hard for abotu a minute and then relax. this is due to computer control.
yes it's ok to drive when the auto choke is on, but that is a time where we should be VERY gentle as most of the engine wear happens around then.
@SLR
you are a very patient person:P