My 99 Tahoe has a weird quirk in the cold. WhenI drive it in the cold temps(below 25f)I will sometimes get a LOSS of power steering for a brief moment. Very scary the first time it happens. Easy to over compensate when it occurs. This momentary loss of power assist is troubling. I have bleed out fluid , checked fluid levels,, changed the drive belt, and am wondering if others have experienced this and there is a FIX. I contacted GM because of the safety issues and they acted like I was the only one on the planet with such a problem....Thanks

 

Could be a faulty hand wheels speed sensor (HWSS) in the lower part of the steering cloumn.
This sensor sends information that controls the amount of power assist provided, if it is faulty you will notice what you describe.

If this isn't it then you may have a bad spool valve which will require a new steering box.

 

ZX1100F1, I am not familiar with "hand wheels speed sensors" what do they look like? Can I do an easy replacement? How much do they cost? Is this a salvage yard possibility? Thanks for the reply.