uneven steering effort

(’07 Cobalt LS; rack & pinion, with electric power steering.)

Lately, I’ve felt there might be a hitch in the steering, occurring when straightening out after rounding a corner. The effect is subtle, and possibly all in my head.

So, I put the front end up. With engine off, key on, I can turn the steering wheel. But, at about +/- 45-degrees rotation, the effort needed to turn abruptly substantially increases, and remains at the higher level beyond that point. It isn’t hard to turn; just, there’s a noticeable change. If it matters, there is negligible slop in the linkage. The anti-theft steering lock occurs at ~90 degrees rotation.

Anyway, that’s the question: is it normal for steering resistance to change like that? Thanks.