I just picked up a 93 hatch for my girlfriend, it failed the etest horribly, was running way too rich. The guy I bought it from said you only need a new cat and it will pass. I changed the cat, injectors, fpr. The car still failed horribly, I started reading and every where I look it says the 92-95 cx model has a 1 wire o2 sensor, but my car has a 4 wire. I'm thinking motor was swapped at one point a 4 wire was put in, then stock motor/ecu was put back in and ecu is not hooked up right for the 4 wire. I don't know, but I can't afford to change everything on it to figure it out. Could I possibly just change ecu with another model? Any help appreciated..