Awhile back I disconnected the battery from my 13' Fx4. The ecu seemed to have drained. Later getting a inspection sticker, mechanic tells me can't do it cuz the computer is not ready. Tells me to drive more. Did 60 miles. Came back and told me it's not ready yet. My scanner says all is good except catalytic monitor reading Warning! Could it be during the last year the cats might have bad o2 sensors at 64,000 miles.?? Bad gas mileage also 8/9 mpg city. No rough idle, no egg smell, no tailpipe smoke.

 

> Could it be during the last year the cats might have bad o2 sensors at 64,000 miles.?

Though I could see they were recently replaced on my used 2014, I had to replace them (BOSCH). I do not drive much, but, the replacement #2 BOSCH O2 sensors bough from Advance seems to be doing okay. What finally set the emissions after literally 100s of miles driving and doing the suggested drive parameters, was flooring it from a dead stop.

> My scanner says all is good except catalytic monitor reading

exact code listed would help

Being in Boston, you probably have the special winter gas mix, I would look at putting non-alcohol gas in the tank along with a bottle of guaranteed to pass. I have used this combo in the past to pass vehicles for other people too.

https://blog.amsoil.com/the-differen...mer-blend-gas/