Based on your videos, you look to be running pretty lean. I wouldn't call the "cold start" a "start" either. That's a stall.

In your earlier video, when you are blipping the throttle, you shouldn't be getting that hesitation/lag either. It's hard to tell from a video, but it sounds to be running a bit on the rough side as well.

You can test the theory. Dump a tablespoon or so of gas down the intake and try doing a cold start. If you get more than that sneeze you got in your cold-start video, you can bet you have a decent vacuum leak somewhere.

__________________
Current stable:
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Gone but not forgotten:
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