Some thoughts on O2 sensors;
Basically there are 2 on each bank , before (upstream), and after (downstream),the converter. The downstream ones arent critical.... they just tell you the cats are working or not (MIL ) The upstream ones are the ones that give you fuel trims , and run the car in closed loop. Per Lonnie Doll, who is arguably one of the best practical tuners of Fords in the world, by his own admission, you should ALLWAYS use OEM Ford O2 sensors ...... Well lets modify that some , and say at least on the upstream ones, and be doubly sure that they are the exact calibration for your model and year. I would not try to use Autozone or advanced auto one size fits all ("But theyre very good Bosch sensors!") as the upstream sensors ...
Now, you frequently can clean them and get a better performance , and xtra miles out of them. You need to use a LP torch ,like a Bernz o Matic.... but no hotter torches as there is risk of damageing the sensors. There is a "basket " around the actual sensor to protect it. Usually there is black soot on the basket... mine had a rusty orange
coating. Never saw that before, hmmmm? must have been some of the crappy gas I have seen around here lately (too much sulfur) , or possibly some leaded gas in the system alomng the line? Anyhow I carefully set the torch to a slightly smaller , rounded blue flame , and gingerly passed the sensors basket over it, till it just started glowing a dull red, then moved on to 'anudder' spot, beinbg careful to not over heat the thing...bright red is kinda much. Heres a before pic
Heres an after pic
Was there a difference? you bet yer A55!! before it was kinda flat feeling, now sharper reaction to throttle , stronger, and more POWER!! the butt 0 meter said outstanding! My guess, no codes , about 30 K on the sensors, would have lit up in a few thousand more, now I think maybe 10 to 20000 miles more of service , and abetter performing car to boot.