I've replaced all tie rods and ball joints, idler arm, new tires and alignment, but i can move my tires from side to side (hands at 9 and 3) while jacked up. Starting to vibrate bad and hard to keep in my own lane. No play with hands at 12 and 6. Its a 98 blazer 4x4.

 

What about the pitman arm,center link linkage?If the steering gear box is the original one..Possibility it can re adjusted or you`ll just have to replace it. My steering wheel was pulling to the right before I put new tires on it.Got an alignment, the caster(Not the toe) was off 6 degree`s.It hasn`t pulled to the right sense.Maybe the alignment wasn`t done right.Hard to say sense I can`t look at they way the tires look.One more thing I forgot, the rag joint may have to be changed also.

 

cant adj. steering box and they are known to go bad. Also the center link holes can oval out

 

Definitely check the rag joint as a possible problem. I thought the 9 to 3 o'clock movement was aan indication of a worn wheel bearing hub. You mentioned bad vibration. How about noise on the highway and at what speed?