I recently bought an 04 with the 3.8 in it, and it runs really rough. I tried replacing both the front O2 sensors, but I still get the same codes. Anybody have an idea on what I can test next?
Since the O2 sensors have been replaced we should for the time being assume the O2's are good. IMO you should focus on a connector or wiring problem. Pay special attention to the list of possible electrical faults with double attention to "short to VPWR".
Do you have an ODB2 sensor capable of monitoring real time data? If so monitor the actual O2 sensor voltage. What is it doing? Is to stuck high or low and never changing? This could give a clue if looking for an open or short.
P1152 - Lack of HO2S-21 Switch, Sensor Indicates Rich
One tool to use is a mechanic's stethoscope. Probe around the areas that are suspected of leaking.
Honestly I don't see that a single exhaust leak could cause the "strange/exotic" DTC codes. Now it does seem possible that there is an exhaust leak PLUS an additional problem. But in the same vein, don't be surprised if after repairing the exhaust leak, there are still codes.