Steering problems

[lane224]

1986 k10 brand new 4" lift.
When making left turn Truck will suddenly jerk to the right and steering will get sloppy. Doesn't happen every time. Checked rag joint and all steering components all look good. Bad steering box? Power steering pump is a bit overfilled. Not sure what else to look for. Lift was installed before I bought truck so not sure if these symptoms were there before. Has the 4" raised steering arm. Is it possible I need to change the drag link also ?

Any help would be appreciated.