Re: 2005 GC runs so bad
Quite some codes set. Did you use a scanner to read the codes, or doing the key dance? I would first reset the codes and testdrive, to see which codes are hard. It would also be wise to check the fuel trim figures, since bank 1 has a fault code for being rich (P0172). Check if the O2 sensor 1-1 (bank 1, sensor 1) is changing its voltage rapidly from 0.2-0.8V.
The P0404 has to do with the EGR valve, it could be carbon buildup on the valve, preventing it to open or close.
Also check for any vacuum leaks in the inlet and loose/broken vacuum lines.