Have a few DTC's P0121, P0521, P0523

[SDGTP99]

I have an idea what is causing my car to run like pooh;

-DTC P0121, which is for a bad TPS. I just ordered a new TB to fix this issue.
-DTC P0521 & P0523 are both for Low oil pressure/low oil level/faulty electronics.

I haven't done much to the car lately except an oil change, and the oil level is fine. Could a bad throttle body be causing all of these problems? Could it cause the engine to constantly switch from 4 to 8 cylinders, consume oil & lose pressure? I honestly don't know. But, when driving it does feel like the car is either knocking, switching from 4 to 8 cylinders or shifting. Any help at all will be appreciated. =]

[98buicksupercharged]

did you check your engine level....

[98buicksupercharged]

engine oil level

[SDGTP99]

I did. Oil level is fine. Guys on LS1Tech say the P0521 is caused by a bad Oil Pressure sensor. Still unsure what caused the P0523.

[SDGTP99]

Replaced oil Pressure sensor. Car suns a wee bit better. Still acts like its missfireing and the tailpipes are turning black fast. Doubt that's caused by a bad TPS. I bet I have a nasty consumption problem...

[TML529]

Had my Throttle body replaced under warranty around 45k and just had my oil pressure switch replaced.

[SDGTP99]

I replaced both out of pocket. Not sure I needed to. Codes went away after cleaning TB and adding a quart of oil. =\