Steering

Most likely the intermediate shaft binding some. Take it apart and grease it.

You can almost bet on it being something worn in the front end, not a boost problem. Partly seized ball-joints/king-pins are known to cause that symptom

On my 04 Silverado D/A I was getting something like this on gentle turns. Took it in under warranty, they greased the intermediate steering shaft. That lasted for several years but started up again when I was out of factory warranty, it was replaced with a updated part on my extended warranty. That was about 50K miles ago, been good to go ever since. I'd check that first.

DJ

Replaced $3800.00 worth of front end parts last year.

Only happens at speed above 30mph.

Almost like an ice patch.

I have a '99 tahoe, where I could feel a intermittant catch/bump in the steering - pretty scary. The dealership found that a wire to the power steering sensor was damaged ("pinched" was the mechanics description). Fixing the wire eliminated the problem.