I own a tiico van, and was getting only so gas mileage So I disconnected to 02 sensor and drove around for a couple of days.

Not big difference.

Well I hooked it backup, it suddenly seemed to go from ok to terrible.

I need some help. I didn't do anything!!   What happened?  Did something else happened at the exact time it did this? HELP!

Starts just fine, but simply does not like to accelerate.  Idles fine. Bogs down when I step on the accelerator. Almost dies. Sometimes backfires.  

Once I am patient and get to speed on the freeway, seems to hum along just fine, but gutless.  I worry about hills.   If I get off and stop, well getting going, esp on a hill is terrible. Seems if a get the revs up, it "catches" and gets going, but not anywhere like normal. 

Pulled one set of plugs,  all sooty.  Put some new ones in. Same performance. Pulled them a day later, and the look ok - may be a little dark.

I have looked for loose wires/broken wires - can't find any. I unplugged the o2 sensor again, no difference.

Could this be bad injectors/fuel pump? (I have new injectors from jetta about 1 month ok)

Fault codes:
Most Always
00533 idle regulations N71 090 adaptation limit surpassed (often return immediately upon clearing)

less common
00537 Oxygen system regulation, 27-00 implausible single

0524 knock sensor G61, 3100 open or short to ground.

0561 fuel mixture adjustment.
    15-10 adaptation limit (add) not reached.