#1 is the O2 sensor, but the strange thing is that it shouldn't matter at startup. Besides, your sensor is fairly new?? Even if it's bad, it seems like that shouldn't be related to the startup business.

How old are the plugs? Sometimes if they're fouled from flooding, they don't work right again. Even after drying out. If they're not real new it's a cheap thing to try.

You just found how to read codes... Are you sure it's a short blink? One long flash is 10 = intake air temperature sensor.