Ground from block to frame is a good thing anywhere.

I have a rust free Roadmaster for sale, but was hit in driver door... and a rust free Caprice wagon for sale, needs motor... both white...

Just probe the knock sensor wire or plug while connected for about 2.5 volts and 5 volts disconnected. Just print that stuff for your dad, if he has been around a Digital Volt Meter it will all make...

That's the procedure for that circut, you've already done the advanced part which was replace PCM, knock module or Knock sensors. I know you said you checked wiring, but do the voltages and ohms....

Looking at data does not show any ground issue, but you do have issues! That code 43c active seems to be messing up everything! Looks like a limp home situation as your closed loop, right and left O2...

Have you cleared codes either by scan tool, TP or removing power from PCM? I don't remember where you were and don't want to confuse you with someone else...

Sure, look under flags for "Knock...