[pcmos]

I've noticed recently that my steering wheel has what seems like an excessive amount of play. Additionally I keep getting a "service stability system" warning message on the dash. The code stored on the system translates into a steering wheel angle error. To try to clarify and rule out some common causes I'd like to start by saying this is not a "center-only" issue.
My first thought was that the rack and pinion was wearing out around it's center position (143k miles). After giving the preload adjustment a little tweak I was able to clean up any slop in the rack. Here is how it behaves:

1. If I sit still in the car and gently rotate the wheel from side to side it allows about 5 degrees of rotation in either direction before there is any reaction at the wheels. With the preload on the rack adjusted you can rotate the wheel about 5 degrees plus/minus and then you feel it engage the rack which is now nice and tight.
2. While driving the car it doesn't really matter if I am turning through a curve or driving straight on the highway, I have plus/minus 5 degrees of rotation of the steering wheel before I achieve any steering response. This means I am often swinging the wheel back and forth at ridiculous angles to make tiny corrections as I am driving.
3. I pulled up the rubber cover on the intermediate shaft where it splines onto the rack and pinion input shaft. My friend jiggled the steering wheel plus/minus 5 degrees while I held my hand on the intermediate shaft. I really couldn't tell if the play was in the shaft or in the rack.
4. This past week I have been getting a "service stability system" message. When I connect to the stability system using my enhanced scantool interface I find a code that translates into a steering angle mismatch code for the steering angle sensor. In other words, the car is detecting that when I am going straight, the steering wheel is cocked at a screwy angle.

Alignment has been checked multiple times, I replaced both outter tie rod ends and all of the hardware associated with the sway bar. Tires were rotated and rebalanced. Nothing seems to resolve this issue and it is really frustrating. I don't think there is anything wrong with the stability sensor because the message it is sending to the computer is exactly what I am actually experiencing. I agree with its assessment of the problem, and if I were the computer I would be saying the same thing.

Has anyone experienced the same problem? If so, what did you do to resolve it?