I was experiencing some smoke from the exhaust at full throttle on my 92 100 CS. After some maintenance I'm experiencing rough idle and the brakes are suddenly non-existent.

Ok, here is what I did. I did a poor-man's coolant flush by draining the coolant from the lowest hose then added fresh coolant. I opened the coolant bleeder valve and ran the car with the heat on. I can't seem to get the coolant into the system though. No air came from the bleeder valve. Yes, I know that this didn't really drain all the coolant. That isn't the issue.

I also checked the plugs for any issues. None to be seen.

Now, the idle is rough and the brakes are functioning at about 25%. The dash readout says "Brake Light".

I don't see how any of this could have affected the braking system or caused the idle to go wonky like that.

Any ideas?