2005 5.4l SuperCrew. Changed Plugs and now check engine light is on. Gives code for the o2 sensor(p0420) I have noticed that there is more of an exhaust order present than before. Truck runs and sounds good. Can something trigger the o2 sensors that i can check before i replace them??? Thanks
also i reset the computer and it takes about 50 miles for the cel to come on again. Can cats be bad?????