knock retard at 10PSI!

[bholker]

I'm working on getting rid of the knock retard I see at only 10 psi of boost. 92 octane, o2 volts around 800 to 820 at wot. Some time ago I put in some 110 octane and the knock does go away. So I'm assuming it's not false knock.
But what's up? O2's seem plenty high, and I still get this knock. I've seen up to 7 degrees show up before I let off. I can't get over 50mph and I'm off the throttle??
Will an O2 sensor fail high? If it's reading 820 and really it's lower than that is the ECM pulling fuel thinking it needs to lean it out?
I do know that with the fuel pressure adjusted up the max wot psi I get is 52 or 53. Walbro340 is on order.
I've got a ramchargers translator, and LTI 3" Maf.
Any input?
Think I've got some junk gas?
I plan to replicate my test w/ the 110 octane before I get too carried away, but am open to ideas if anyone has any.

 

[scottyb]

I'd start with a good fuel system cleaning. Add the walbro, and go from there. I'd expect a weak/dirty injector to lean a single cylinder and cause knock. I used the red stuff at NAPA to clean injectors and had proof that it worked. It says to use 1/2 of the bottle per tank, but I used the whole thing and stay out of boost on that tank. On the other hand, I never had a problem like yours. Maybe if you suspect them you should get them professionally done.
Plus get a power plate.

 

[1badTTA]

Toluene or Xylene work pretty good for cleaning the injectors and also boost your octane at the same time. I would suggest a tank of "home brew" for your diagnostics.