Various Issues with Power and advancing Spark (LZ4 3.5l GenIV)

Hey guys, I have a 2009 Pontiac G6 with the 3.5l v6 with about 183k on the odometer.

I have been working and tuning this vehicle for a while. I replaced injectors with OEM injectors, added an exhaust to it that I welded. That's about it on the side of 'mods' and maintenance has been often. It eats about 1qt oil every 1.5k miles. I change the oil pretty often at about 3k mile intervals. Always use Mobil 1 High Mileage Full synthetic. I have cleaned the MAF sensor, cleaned (for the most part) the upper intake.

I got an MPVI3 so that I could get myself into tuning. Figured starting on a cheap vehicle would be best, and so I started learning. Using LTFT I have been able to better work on my idle as it was running 10% rich all across the board. I am still working to get a wideband kit and install that.

As I am tuning the spark, I noticed even with high octane, I end up retarding like all of it as I am getting knock on 91 octane (The highest available at my altitude). Is this because the engine is so old, or because the fueling is off? Does improper fueling affect spark? Here is my current tune high octane table VS the stock tune high octane spark table.
Attachment 143377
This is that tune file even had knock on that, right around that higher area and even some that is retarded over 2 degrees.
Attachment 143378

Over a long trip I had got a random misfire. This happens very rarely. Could this be from knock?

Can provide tune files upon request.

Post the tune and logs you have.

If you're seeing only small amount of knock, it's likely that it's not real. There could be vibration from worn motor mounts or other things that the knock sensors are picking up.

You can play around with commanded fueling at WOT too. Sometimes a richer mixture or leaner mixture can make it all go away too.

Also that's kind of a lot of oil consumption, heard of a lot worse but it's a bit. Makes you wonder if it's getting past the piston rings, valve seals or the PCV system. Switching oil brands could be a worthwhile test and even running a Liqui Moly engine flush to see it can clean up some things.

Current Tune (Still tuning spark as of right now, so its got matching octane tables) and matching log file - Attachment 143384Attachment 143385

That kind of KR you're seeing in the logs isn't too bad overall. This may help. It's based on stock spark map with modifications to VCT.