Engine Codes

[jasong40]

I have a 2008 Pathfinder V6. Little history on it... It overheated couple months back and both heads became warped. I had the heads shaved and got a kit with new gaskets, ttensioners,water pump, chains etc. I put the engine back and was running rough with no power so I checked the catalyst converters and they were Clogged so I cleaned them now jeep has power but running rough so I changed all the coils and plugs and the jeep was still running rough and gave code P0301 then swiched back to the old coil and received code P0304 then changed that coil and received code P0302 changed that coil and jeep is still running rough with the same P0302 code can anyone help?

[smj999smj]

I'm not sure what "cleaning" the converters entails. Usually if they are clogged, you need to replace them. I would do an exhaust back pressure test to make sure there is no exhaust restriction before doing anything else.