Not saying it is your culprit, but logic would say, just because you are no longer tuned and that the problem was there before, does not mean that incorrect tuning was not the culprit when it was tuned... Not sure if that statement made sense or not. But basically a setting like (I have MaftPro not sure of differences of options) but I have an After-start Enrichment, perhaps when it was tuned something like that was not set properly and did not show up until weather was colder, but now you say it is doing nothing for altering translation, so the setting issue could still be the issue...
I am no grammar king, so I hope I got my thought across to be helpful... I guess I would try to see what happened with a little starting fluid, does it start right away?
This may be a compilation of issues, as cranking for a while to start and not idling for the 1st few seconds I am not sure are absolutely related (but certainly can be also), so my other thought, which you went down the right road IMO on swapping the CSI, but it might be a good idea, if you have not already, to check with a meter that proper voltage is going to the CSI when it should be.
