Running rough after stereo install

[Kss0x00]

I recently installed an after market (Chinese 7010b) stereo in my girlfriends 09 yaris which now seems to be idling a little rough and she says the steering is randomly "really tight"/ hard to turn the wheel. I wired the stereo according to the diagram, but there was a third connector plugged into the back of the OEM stereo that I can't find reference to anywhere (connector had 5 wires of about 20 possible openings for wires) that i just left disconnected. Car is manual transmission if that matters.

Is there anything related to the stereo that would cause these issues? Or does anyone have any troubleshooting ideas?

TIA