Here's my setup:
98 C5, 229/229 .578 .578 112 cam, built tranny with vigilante 3600, longtubes, ORY, ls6 intake and a wet kit.

My car was tuned without the air conditioner belt and I installed it a couple weeks ago. Now at low rpm's the car runs really poorly. It pops and hesitates.

It throws the following codes:
P0174--fuel trim system lean bank 2
C2120--TPM system malfunction (no sensors received)

I think it also threw the codes for o2 sensors; but I deleted them and they haven't come back again.

Would these codes cause the car to run like crap. If I floor it, it runs perfectly.

How do I fix these and what would be causing them?

Thanks for any input.