Engine light only comes on once mal 13

[psycho6cyl]

The engine light only came on once,but scanmaster says mal code 13 which i believe is 02 not reacting fast enough.. Just curious why the light never really comes on but scan master says theres a code.. also 42 was showing up not all the time..

 

[Bescurred]

The O2 sensor is on it's way out. Eventually the light will come on and stay on. I use to run leaded race gas a lot and would buy a lifetime warranty one.

 

[psycho6cyl]

io have a replacement and its getting changed this week.. thx