Damn PA emission testing

The LGT threw the codes:

P0325-knock sensor- i Got a new one no big deal

P1133-this a O2 sensor code

Does anybody think jsut replacing the O2 will solve this? Does this have to do with me installing the headers recently?

Step 1: Unplug the battery.

Step 2: Get under car and check wires leading to O2 sensors.

Step 3: If all looks well with the wires, replace O2 sensor.

Step 4: Plug battery back in.

Step 5: Rock on!

It could have something to do with the headers if you pulled damaged the sensor or the wire. After installing the header you should've removed the battery cable for a bit anyway, resetting the ECU so it will acknowledge any changes in the exhaust gas. If the new headers are attached to a full blown exhaust then the backpressure might have been reduced enough to increase the emissions the engine puts out. Backpressure helps keep unburned or semi-burned exhaust in the cylinders. With a free flowing exhaust, the engine can rid itself of these particles and start the next compression stroke with more fresh particles from the intake, instead of reusing old particles retained from backpressure. This increases power since the gas in the chamber is fresh thus containing more potential energy, but reduces gas mileage as you are losing particles that still have some potential energy to the exhaust. The O2 sensor is looking at this extra unburned gas as something is wrong, thus throwing a CEL. Resetting the ECU might recalibrate the ECU to the new inputs from the O2 sensors. It might make the ECU realize that this is how the engine runs, and deviation from this new value (As opposed to the value given with the old headers) would denote an engine malfunction.