Hey just bought a new 98 coupe and its got a b18c1 swap that is straight pipped. I just got a CEL with code p0420. I dont have a cat and I cant figure out what the hell I gota do to fix it. The dealerships out here give out complimentary lipstick so you look pretty before they stick you, so thats not an option. How do I fool the ECU into thinking it has a cat anyways? Emulate it? or should I even be messing with o2 sensors? The car runs like **** right now and bogs, pretty sure its running rich my fuel economy is horrible... Getting 400km per fill

 

Buy a catalytic converter