Help with oxygen sensors and/or EVAP systems? - 1997 E36 M3

[IfIHadSomeBacon]

I plugged a code reader into my 1997 E36 M3, and got a few codes:

P0455 OBD-II
Evaporative Emission Control System Leak Detected (no purge flow or large leak)
Read more at: http://www.obd-codes.com/p0455

P0133 OBD-II
Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)
Read more at: http://www.obd-codes.com/p0133

P0153 OBD-II
Oxygen Sensor Circuit Slow Response (Bank2, Sensor1)
Read more at: http://www.obd-codes.com/p0153

What is are the problems that are most likely to happen in M3s? I have heard a lot about oxygen sensors, but on a scale of 1-10 does anyone know how complicated these problems are?

Sidenote: The airbag light is on, is there an easy way to know what kind of problem is causing the airbag to not go off? Or if it is just turned off?

Thanks!

[thejlevie]

The O2 sensor codes sound like aged pre-cat O2 sensors. They are a scheduled maintenance item with a replacement interval of 100k.

The evap code could have been set by a loose gas cap. Clear the code and see it it returns. If it does the first task should be to look for leaks by smoke testing the fuel system.