my exhaust only has 1 sensor hole and i have 2 o2 sensors.. stock dx wireharness.. could i splice the other o2 sensor wires into this 1 o2 sensor? would that work ? gas milage sucks..

 

As long as your primary o2 sensor is still plugged in then the 2nd won't affect the performance. You will still get a check engine light with the second one not plugged in, but it won't mess with the ecu settings.

 

actually i have no CEL at all.. even though its unplugged im runnin stock harness with stock ecu still.. and idea on that?