Help with strange knock???

Kinda hard to get a handle on this one (for me at least). Is this knock only felt through the steering wheel or also through the floor boards to any degree? ANd does it occur when you apply the brakes or when the car actually stops, or ????

I only notice it in the steering wheel. It feels like the motor is jumping around and maybe a header or something is hitting the steering box. feels rather heavy. I do not feel it all the time, mainly when I'm coming to a stop or slowing down after opening her up. Like as the motor is settling back to idle conditions. I do not feel any of this through the brakes. As, i said earlier the motor is pretty radical and does jump around a bit and I assumed it was a header or something knocking into the steering but it isn't. I just recently put it together that the braking had some correlation to it. I am going to check the steering coupler as stated above. It has to be that or something in the suspension itself.