Part throttle knock w/ rich low & mid fuel trims

[King Salami]

I've read innumerable posts on part throttle knock. I have not read any that are accomanied by rich lo/mid fuel trims, which is what my problem is.

Here's my story:
When I converted to my 2G MAS & 560 injectors, I had Nate & Jeff burn me a Stage 3 chip for that setup (set to 40-42 psi fuel press to give me a bit of fuel press tuning room).
Since then, I'm still running too rich on my low (81) & mid (87) fuel trims. The high trim is at 94. O2 feedback trim cycles from about 45 - 80 unless I'm cruising on the freeway, then it stays around 85 - 125.
I can't figure out why I'm running so rich down low! I've also got a nasty part-throttle knock. With a load on the engine in 1st & 2nd I get 15 - 40 counts of knock coming out of vacuum. If I back off & reapply gas or just initially stomp the gas, my knock counts are much less. My WOT knock is pretty standard - about 7-20 counts above 5000 rpm.
I know the injectors are Evo 560's, My timing is 5 deg (I experimented w/ 3 degrees - no change), I've got new plugs (gapped correctly) that all look uniformly grayish tan, I've got no major boost leaks. I have no sputters or jerks (ignition). I also used MCCC about 3K miles ago, but I'm assuming that all that extra fuel has already carboned up my cylinders. I've swapped in another chip for 550's (even richer). I cannot find any indications from my logger that anything is amiss except for my abnormally rich fuel trims.

Can a faulty EGR cause this rich condition and the knock? I cleaned & tested mine - it reacts under vacuum, and the thermal valve that controls it is working fine. I backed out the MAS screw all the way - it got me a little leaner O2 feedback trim up top, but the low & mids didn't move.
Any ideas to get leaner (I don't have the cash for an AFC right now) & get rid of the part throttle knock?

 

[weith1111]

Have you upgraded to 3g lifters yet?

 

[King Salami]

I used to have lifter tick, but not anymore.
My lifters have been very quiet since I've been commuting 20 miles to work every day. They were noisy when I had a 7-minute drive to work.

I'm positive this knock is real - it consistently happens only when under load in 1st & 2nd with part throttle. I can modulate it with throttle inputs, too.

 

[weith1111]

Well rich knock is possible, especially with how rich you appear to be running. Turn your FP down? Check for boost leaks, if you have any, they will only be adding to the richness.