Hello everyone,
I have owned my 1994 base auto for the past two years and recently I have been having spark knock issues with my vette and I am not sure which way to go about this. She has around 57,000 miles (15,000 put on by me). Pretty much whenever I give the car power, she runs a lot more sluggish then usual and makes the dreaded knocking noise. The last time I took her out for a long drive, this problem was further amplified after I filled up and the car would not accelerate even though I almost at WOT at pretty slow speeds (20 to 30 mph). Previously, I would occasionally get intermittent codes for the egr which I ended up replacing since the diaphragm would not hold vacuum. That code has not come on since, but I get an h13 on module 4. This code also did not reappear when I was collecting live data when the knocking occurred. I know it would make logical sense to refer to the factory manual and follow the chart, but I wanted to know if my eehack data points to that or anything else before I get under my car.

According to the previous owner's records, the stuff he replaced that could be related to this problem includes the gas sending unit, thermostat, water pump, spark plugs and wires, ignition module and installing a vented optispark. I myself have replaced the fuel pump, fuel pressure regulator, egr, maf sensor, fuel filter and air filter. I also only use 93 octane fuel.

Below, I will attach the live data from both 50% and wot and the cylinder balance test.
Any help is appreciated, thank you.