Magnaflow High Flow Cats

[Tweak1]

If this is answered I'm terribly , I'm sick while trying to deal with the explorer.
So I had to replace my cats due to the intake manifold causing them to go bad. I felt my ,most cost efficient solution was to buy the magna flow high flow cats, and i did the catback with it just for the ease of it all going on smoothly due to the miles on the truck.

2005 Ford Explorer Limited 4.6

My question do I need to run a defouler I think its called for the 2nd 02 sensors?
The check engine light is back on , And I feel the truck has hesitation in low rpms, almost like a miss. I will be getting the code read with in the hour. Crazy thing is my MPG's have not suffered I was getting 19 MPG, last night on the way home from doing the exhaust when this started happening .

 

[Tweak1]

Ok, so it was not the O2 sensor like I was thinking it was.It was a misfire on cylinder 1.
Remedy, So far swapped 1 & 7 COP's, Still had misfire, Than swapped those back and swapped spark plugs, NO code yet. When ford did the intake they replaced all COP's on the even side of the motor along with the spark plugs. So this weekend i will replace the odd side with new plugs .

Im pretty impressed with the magnaflow, it's still quite, and roars when u get on it some. I was worried it would be to loud.

Also I picked the magnaflow cats up for 488.00
And Magnaflow Catback up For 410.00

Frickin Sweet