P0404 Exhaust Gas Recirculation Circuit Range/Performance - DTC Code
OBD2-OBDII Engine Light Trouble Code P0742 CHEVROLET - Torque Converter Clutch Circuit Stuck On | Engine-Codes.com
Took me all of 5 seconds to google both of those codes just fyi.
Most likely scenario get a new egr valve and drop your trans pan change the filter and put in new fluid. You might need a new Torque Converter Clutch Solenoid.