Throw 02 engine codes [small problem]

[Firehawk N Wv]

After installing my headers almost a year ago my car thrown a light. The code read for the 02 sensors so i replaced them all. The light went away for some time then it came back and would go off then come back on several times. Now its back and not going off. I had it checked and here is what it read.

P0133
o2 Sensor
CKT slow response
[Bank 1 Sesor 1]

P0138
02 sensor
Circuit High Voltage
[Bank 1 sensor 2]

P0171
System too lean
Bank 1

P1133
Manfacurer Control
Fuel Air metering

Can someone tell me how to fix this coeds and what they really mean. I have an idea of what the mean but im not sure. The one about A/F metering maybe because i have a A/F gauge but that hasnt caused it the throw that code before and it shouldnt. I'm thinking to fix the 02 coedes i should just replce the 02 sensors again. Somone please explain, thanx.

[Firehawk N Wv]

I juat need to know what exactly these codes mean and what I can do to fix them. I'm thinkin all i nded to do is repalce the 02 censor again. If I'm correct 'bank 1' is on the drivers side...