Hey guys,
Here is my problem, please chip-in, need to fix this ASAP, my FX is DD-car:

I cut OEM rotors after I put only @ 5K miles on them, felt like they got warped ... at around 60 mph and up I was getting vibrations. So I cut rotors and I put new OEM pads, even though the old pads were still ok (after 5K miles).
Now at the speed from 10-40 mph I'm getting loud knocking noise from the front wheels, sounds like it's coming from the left side only, but I'm not too sure it's only one side. This knocking noise is exactly in the same intervals as the speed of the wheels / rotors, so it's definitely coming from the rotors - pads. From 50-60 mph and up this knocking noise is gone, but when I slow down to 40 and down it's back.

I even put the old (OEM) pads back to see if this could be new pads problem, but it's doing the same thing - even louder I guess. Vibrations at a higher speed is gone, so I think rotors were cut OK.

Anyone experienced similar problem, could this problem be because the rotors were cut, or some other suspension problem???

Thanks in advance !!