Knock Knock

Ok I know knock questions on here are like a broken record. I have read several posts by searching but cannot find one quite like this. Anyways I have been having a knock problem. Today I was out going about 30 mph and rolled into it and it started to knock. I was running about 21psi on 110 octane gas. O2s were 835 but the knock gauge was deep into the amber and it retarded 9.1 d. So I came home because I figured it had false knock because the 02s were so high. I then lowered the boost down to about 15psi still on 110 and took it out for a couple runs. The first run I rolled into going about 20 mph and it slightly knocked still in the green in the gauge and it only retarted approx 2 degrees. Then I stopped and left at about 1psi and when I let it go it immediately went strait into red on the gauge and retarted 12 degrees and the the o2s were at 385. The boost on that run was still lowerered at this time. So I have no idea where to start. The o2 sensor is pretty new. At first I thought I had some false knock because of the high 02s then after that last run I dont know what to think. If you have any ideas I would love to hear them.
Check your f.p. via the gauge taped to windshield method. You could have a pump fagging out on you.
I have a gauge inside the car and it was reading near 70lbs once the second pump comes on. So I think there should be plenty of fuel pressure.
I also have a fp gauge under the hood on the rail. Tomarrow when it is light out again i will tape it to the windshield and check that out. But i think that the fp is fine judging by the guage in the car.
knock knock boom

figure it out soon. mine did the exact same thing and after two days of goofing around i was picking up cast iron off the road. crank split torn block ripped ic.
Start going thru this list.............Turbo Regal Knock Problem Check List
1. Start-up knock? Normal and usually caused by the starter engaging the flex plate. Usually sets off 1-3 lights.
2. Possible bad ECM or ESC module. Test with good working units.
3. Exhaust rattle – check the down pipe, tail pipes, and have engine tie down strap
4. Boost creep especially top of 1st gear on 1-2 shift.
5. Lean air/fuel mixture.
6. To low octane gas – bad pump gas – try some race gas
7. Too much timing in chip for fuel used. Try different chip.
8. Try cooler spark plugs – use only AC Delco (R43-TS or R42-TS)
9. Gap plugs to .035
10. Check torque converter bolts to make sure they are tight
11. Loose harmonic balancer. Make sure torqued to 200 ft/lb Is keyway secure?
12. Check internal engine noises like timing chains (roller), lifters/rockers, etc.
13. Damaged knock sensor
14. Check fuel pump pressure and volume
15. Proper torque on knock sensor – 14 ft/lb
16. Check Alternator voltage: 13.8 - 14.5v
17. Check computer power wire - they can break internally.
18. Troubleshoot the computer connector power wires and ground wires.
19. Swap coil pack, wires, plugs w/known good units.
20. Swap MAF with known good unit.
21. Check battery ground connection @ block (clean/inspect).
22. Check/change battery cables (both).
23. Are there MAF leaks in the inlet tube?
24. Are there vacuum leaks. Use carb cleaner or WD-40 & spray everything. Does the rpm change?
25. Disconnect the main injector harness - inspect, WD-40. Check for moisture in main connector.
26. Disconnect the coil-pack connector - inspect pins & spray w/WD-40.
27. Is the cat still installed? Is it good?
28. Have you performed a leak down check?
29. Do the rockers open/close? Do we have a wiped cam lobe?
30. Is the boost/vacuum steady @ idle?
31. Is the engine over revving? Should be 4,800-5,200 rpm
32. Carbon in cylinders? Clean with GM engine top cleaner
33. Inter-cooler dirty? Clean inside inter-cooler and fins
34. Oil in intake tract?
35. Check for exhaust leaks, cracked header
36. Battery good?
37. EGR valve in working order?
38. Check that no cables, wires, etc are touching the knock sensor
39. Blown head gasket? Compression test. Should be around 150.
40. Injectors flowing/working correctly?
41. Check vacuum line to fuel pressure regulator for cracks
I just did a quick look through on the checklist over some of the simpler stuff and found that my mufflers are rusting through and rattleing a bit. Could something that far down the driveline cause all this knock??? I just got my car out and you can hear them rattleing espically when the car is cold at startup. When this is going on at idle it doesnt show nothing on the knock gauge. But under hard acceleration I guess if it rattles worse it could show up as knock. I dont know????