Slow response code always

[nghtshd88]

About 7 months ago I replaced my driver side cat that was bad with a high flow one from flowmaster. The passenger had already been done with the exact same one a while ago. A few months later I got the slow response code for the front oxygen sensor and then it never went away. Changed the sensor (motorcraft again) and now every few weeks it comes for 2 days and leaves. The sensor is pretty much in the exact same spot it was before. Is positioning very sensitive on this car or can a common issue cause a slow response code? To me its always been the sensor going bad only.

 

[hite337]

I have the Thunderbolt high flow CATs and have not had good luck with them. The codes I get are p0420 and p0430 lean codes. I know a few others who have had the same results. I don't think these cars like high flow CATs. I am going back to OEM style CATs in the next few weeks.