2002 Infiniti G20 Service Engine Soon Light

5 days after I changed the spark plugs, the SES light goes on. I used OEM Spark Plug PFR6B-11 NGK which I ordered online. However, these plugs are not listed on the owner's manual. I verified that the gap is 0.043" (Is it correct?). The scanned code from an auto parts store indicates bank 1 sensor 2. The guy told me it is the oxgen sensor near the catalytic converter problem. He reset the code. I subsequently changed the spark plug wires, distributor cap and rotor also. The SES light came back on after one day. I wonder whether the spark plugs that I used (the fact that it is not listed on the owner's manual) is causing the problem or not. If nothing else, my next step is to take the car in to the dealer. Thanks in advance.