UPDATE :
Wanted to give you guys an update and see what you think. In my last tank of fuel I added Redline S-1 Fuel Cleaner, which I normally do before an oil change. During that tank of fuel, the knocking was gone 90% of the time, and when it did knock if was very quiet, you could barely hear it unless you were trying to like I was. The Redline helped the noise, alot.
I ran that tank down, then filled up with normal 87 octane from Shell. Once again the knock is back, just about as bad as before. So I'm back at square one. I had my brother listen to it (who has worked on cars for about 15 years) and said it sounded like pinging to him, but didn't understand why the premium gas and Redline only helped the problem for a small amount of time.
Before I goto a dealership and get racked over the coals, I'd like to eliminate other possibilites. Could a bad oil filter cause this (bypass?), spark plugs fouled, Seafoam the engine, valves need adjusting? I'd like to take this on myself, I don't have a trusted mechanic so I'm sure somebody would just take me for a ride, and likely not even fix the problem.