A lot of these codes remind me of my dying battery I encountered on my C5 A6. The battery was slowly giving up and causing all kinds of weird errors and voltage issues / ecu communication problems, etc.
How good/new is the battery? If older and a battery tester shows it's below 50% capacity it's time to get a new one, reset the codes and see what comes back.
I also would check the wiring from/to the ECU and make sure it does not have any damage.
If the ECU errors still come back I would have to agree that maybe you should check the computer as you should not be getting errors from it if something mechanically is failing.

 

sheldon,

Thanks for the input I had been told the battery was replaced recently but I think I'll have it checked to make sure it's not low on a charge. I did clear the cluster of codes from 05 yesterday and it took out my EPC light. I'm gonna clear the rest today and after I get coolant and fix a oil leak I'm gonna take my car for a drive and see what comes back. I checked the air pressure regulator and it doesn't seem cracked so I will be checking the wiring to/from that as well. Have you ever checked wiring? Not too sure hot that's done/where it all goes. Gonna google and find a wiring diagram of the car today to further troubleshoot. Anyone ever flashed a ECU to stock? I'm wondering if there was a remap or bad flash done to it.

 

Also, VAGCOM codes can be finicky. Did you clear them and see if they came back? I would definitely try that as well. It does sound a lot like when these cars start freaking out due to low voltage.

 

clesred codes and ran for about 15 min, ECP light is still on but no CEL yet, car still drives just as bad. Haven't had a chance to check battery charge. Took my ECU out and heard it rattle sounds like something may have fried inside and broken off these things are sealed pretty tight I can't imagine anything getting into it from the outside I couldn't even open it..

 

cleared codes, checked ECU and heard a rattling inside, couldn't get it open but I think something shorted and came loose inside.