Slow Z28

iTrader: (19)

would a bad quality oil cause anything to shop up as KR on autotap? I know it's a pretty dumb question, but I put in what I thought was some Mobil 1 synthetic my Dad had around but it ended up being Mobil "Drive Clean Oil" and now the motor seems to be making some knocking noises. I had Redline before and I never noticed it. Any thoughts?

Chris