As the title states, these are my issues. I do have the slightly noticable clunk in the steering column while turning. I need to replace this, I know. To my knowledge, the intermediate shaft has never been changed or lubed. The ABS indicator has not come on. I have read quite a few posts with the same issues. I found that if all of these combined, it tends to be a steering sensor, or something related to it. I am hoping to get the car scanned with a Tech II on Monday or Tuesday. Hopefully they can tell what is going on. I will also have my PCM and stat installed for the CASE learn procedure. I already purchased new front hub bearing/wss assemblies today just in case they are needed. But, by reading the related posts, it could be any number of hub asseblies and/or sensors. My question is should I go ahead and try the front hub assemblies or wait. Here is a little history of what I have repaired and replaced on the car.

New EGR Valve
New Mass Air Sensor
New Coolant Temperature Sensor
New Oil Pressure Sending unit
New UIM and LIM gaskets
New Valve Cover Gaskts
New Water Pump gasket and coolant elbows
New Vacuum Harness for MAP sensor and related connections
New Front and Rear Rotors and Pads
Solid Front Engine Mount
Several thermostats
New Catalytic Converter (old one was broken loose inside)
Numerous Instrument Cluster Bulbs

Things that need to be replaced repaired

Install Intense PCM and 180 degree stat
This should take care of the 0420 code
Replace intermidiate shaft
Fix the "long shift" code, I am guessing it is the PCS in the transaxle.
Replace shocks (leaking boots) and struts
Getting close for some new tires
Replace foggy headlamp housings
Recover Sunroof sunshade cover
Replace the "dew wipes" or rubber strips at the base of the windows on all doors
Mine are getting faded

Keep in mind it is very dry and hot here and items dry rot rather that rust out.
My car currently has about 85K on the clock and is driven in West Texas.
If some one has had the issues I have with a positive resolution with out having to make costly diagnosis' by the GM dealership, I am all ears.

Found this post that I never replied back to with an update. Basically just stone cold lazy. Replaced the Steering Wheel Position Sensor, and both front Wheel Speed Sensor/Hub Assemblies. Fixed all my problems! Put new tires on by MY SELF. Place I work at has a truck maintenence shop with a tire mounter and balancer. Pretty impressed with the tires too. They are Sumitomo All Seasons. Really made a difference in the way the car handled. As for replacing the dew wipes, I used some light sand paper to take the loose coating off all of them and made sure to clean them with some de-natured alcohol. I then bought some bulk black vinyl for precut vinyl decals and cut them to fit. Looks really good too. I still need to replaced the headlamp housings, shocks and stuts, and recover the sunshade. Hopefully will do this when Uncle Sam sends me some of my money back.