I have a 98 Z28 M6 with around 92K, the other day the SES light came on, I
had it checked and it showed two different codes one for the smog syst.
and one for a knock retard. The smog code has come up in the past a few
times, but this is the first time for the KR code.
I had them clear the codes and later that night the light came back on.

My question is.. What's wrong with my car? I've done some searching and
found that KR has something to do with timing. My car is stock, I haven't added anything to the motor, and I only use 93 at the gas pumps.

I do know that it's time for a tune up(new plugs and wires).

What else could it be?

Thanks to all that help.

Christian.

 

What was the description of the KR code. Maybe it went bad and isnt sending a signal to the PCM anymore. It prolly needs to be replaced as the 98 had problems with the KR sensors

 

Not sure what the description was. The light is on now, so I will get it check this week.