Thanks miseim. Yes I also saw the EMI signal causing issue with Imp. I tried completely severing the connection between motor and Imp, and then power up the motor completely independently of Imp. I noticed exactly the EMI issue you were talking about.
If I have the DC motor close to Imp (say within 5 inches) then the issue occured. If I bring the motor farther away the issue goes away.
However, I then try just connecting the GND together, and the issue happened again regardless of how far I place the motor away. (I must have the GND and 1 GPIO connected to the motor to control it).
Erick