IMU stops abruptly, is it dead?

I would try adding another pair of pull-ups (4k7) to lower the resistance to about 2k3 which is a reasonable value for 3V3 if the connection between the module and the Arduino is more than about 20cm (8").

How do you power your setup? By USB?

What is a reasonable software to draw diagrams with? The ones I found via forum search mostly have dead links or rather absurd prices for a few uses.

Fritzing (http://fritzing.org) is a nice and easy-to-use program for such tasks and it's free.