ive searched, and i think this problem is dependent on what ur setup is. so here goes. jdm b16a, aftermarket header with both o2s wired up, pr3 ecu, high flow cat. HC: limit 188, actual 172 PASS. NOx: limit 2188, actual 667 PASS. CO: limt 1.00, actual 1.14! FAIL. only failed by .14! new cap, rotor, plugs, and wires at time of swap, 5000 miles or so ago. only thing i can think of to change is o2 sensors. at first my car would bog, and ppl told me to switch the wires going to the sensors. instead i switched the actual sensors, no more bogging. runs a lil rich though. should i have switched the wires not the sensors? also the guy who tested it said new o2 sensors, and racing fuel. but he also said that when CO goes down, HC goes up, and im close on HC also. HELP

 

any one know how to lower my CO by .14?

 

I had that prob too, new stock cat fixed it.

 

i have a high flow cat, new at time of swap, 5k miles ago. stock cat for what car? i have a custom exhaust so welding and cutting.....

 

any one know about the o2 sensor thing? switching the sensors instead of the wires?

 

bump

 

any one have any insight on o2 sensors or racing gas?/??????????

 

I have delt with this problem before. Use a stock exhaust header, and you will see the co's drop. Mine failed because of the custom headers.