I have a 98 328is, 97k miles. with an intermittant steering issue. It seems to happen more after the car has been driven for an hour or more. What happens is if I am just sort of cruzing generally in a straight line at some point I can feel that the sterring wheel becomes tight. That is,, sort of like the power assist is not there... If I then purposly turn the wheel an inch or 2 it then loosens back up.
Could it be the rack is worn or sticking? My fluid lever is ok and there is never any power steering pump noise at all. The belt and idler and brand new.
I did acually drive a 325 that did this too when I was car shopping and didnt know what to think then either.
I have had mine for only 2 months and am getting the mant up to snuff. But now this just started happening.