hyundaitech

P0137, P0141: 02 sensor is Oxygen sensor. Bank one refers to the bank of
the engine with the #1 spark plug. Sensor three reflects the third
position in the exhaust starting upstream and moving downstream. Sounds
like your oxygen sensor behind the main converter is unplugged or the
heater has gone bad. I've also seen a bad splice cause this.

P0742: The generic translation is that the computer thinks the Torque
converter clutch solenoid is stuck on. I'd check a GM manual to see what
specifically triggers this code. I'm figuring it's a performance issue,
but it may be an electrical issue. Once the computer sees this code, the
transmission may revert to full line pressure causing harsh shifts or may
go into fail-safe (only 2nd or 3rd gear available).

P1404: GM EGR valves are known for sticking from time to time. Before
replacing it, first have the car checked to see if there are any PCM
programming updates. I seem to recall that some cars set false P1404
codes. If your egr valve were actually stuck open, the car would
typically be hard to start.

From the sound of things, it sounds like it may be a good idea to take it
to your local dealer to have it checked.