I have a 2000 Eddie Bauer Expidition with the 5.4. I ran my code reader and it popped up a P0156 code, meaning O2 sensor (bank 2 sensor 2). I am unsure which O2 sensor that is. How many O2 sensors on this beast (tried to decipher info on a search but with dial up it sucks) and would it be better to replace all of them? It has 75,000+ on it.
The gas mileage did drop about 4mpg and not running as smooth.
It is the one after the cat on the drivers side. There are 4 HO2S (Heated oxygen sensors) on your vehicle. Two that are in the exhaust stream before the cats, which are used to monitor the air/fuel ratio and two that are after each cat, which measure their effectiveness.
Thanks guys, I can see the O2 sensor through the wheel well, may see if a wire broke, didn't hear an exhaust leak but will check it out. It's got 75,000+ miles on it and may replace and reset light and see what happens.