i have a civic dx 98 sedan 5 speed i put a cold air intake my gas millage go down a little bit but i think is because now i like to hit the gas for listen the sound of the intake but my check engine ligth came on and i now is a 02 sensor but i dont now which one is the computer say PO 141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) please help