I agree with the bump steer answer. heres the thing. check the pivot point of the rack at the inside of the rod. if it is bending(piviting) at the same point of the inside lower contol arm then that part is correct, offen a rack is to short or too long for the frame width.(not in line with the lower control arm ) if this bending point is the same, then check the angle of the tie rod from pivot to steering arm. if this rod rises or falls at a different angle to the lower control arm it will toe in or toe out the tire on deceleraration. there are tie rod spacer kits to correct the angle and lenth of the rod. second thing to check is if the control arms and shock have been installed correctly. meaning they need to be tilted back 7 to 10 degrees, simular to the factory. if they were welded on level(which I have seen) then it will pitch the front end forward ahead of virtical center.tossing the weight on the front end causing the back end to wash out when you lift at the top end.