i own a 2002 f150 with 4.6 in with just over 50,000 miles on it and i had heard after a while the 02 sensors start to become inaccurate and give false readings plummiting gas milage and low end and what not i was wondering if maybe mine are goin bad or what? because im gettin like 12 to 13 miles per gallon and have like no low end torque?

 

I just replaced my original o2 sensors at 152,000 miles and there was little or no difference in gas mileage. Unless you are getting a check engine light, I would double-check all the regular maintenance items first: when did you last replace the air filter, fuel filter, etc?

 

i just put a CAI on and havnt looked at fuel filter

 

I would recommend a good tune up.

02 sensors usually dont fail at 50,000 miles and arent cheap to have installed. Im talking hundreds of $ for a difference that will hardly be noticable. If your check engine light isnt staring you down, then you most likely dont need it.

Tire pressure is a cause of poor gas milage that people often over look.

If you still decide to swap those o2s. Save some money and buy yourself a 02 socket with the slit in the side for your wires to hang out of. Then let your truck sit and run till your exhaust gets hot. This makes the thread area expand. Turn off your truck and carefully (Due to being Hot) place the socket onto the sensor and with alittle force they usually turn right lose. I know afew people that tried to remove them cold and ended up snapping them off and then a pretty big problem follows if you know what I mean.

 

Did you clean the MAF and reboot? Should of been in the instructions..? 12-13 mpg is about right for age and miles. Age counts w/O2 sensors IMO. Age and mileage cross-referenced/based on 12,000 miles per year. Oxygen sensors are good for 100,000 miles based.

At 60,000 I'd go thru everything,- given your model year.

BTW- CAI's are alright , IF you run dry element with them.