Hey guys, I'm new to the board and have trouble with my Ex. Three days ago, my CEL came on and stayed on. The code that we are getting is p0171 and p0174. I know that this has something to do with the System too lean(bank1 and bank 2). What should I start with first?

i am assumbing you have the sohc if you do chances are you have leaky manifold o-rings. and there is a recall to have this fixed. if you have done this areadly than it may be the fuel filter

Well, My check engine light is on. And I went to a machanic friend of mines shop. He scanned my system and told me that I had to replace O2 sensor Bank1, Sensor 1. Thats all that I know. sorry, thought is was my post.

O2 sensors are responsible for a lot of CEL codes (so I've been told).

i am assumbing you have the sohc if you do chances are you have leaky manifold o-rings. and there is a recall to have this fixed.

Is this a new recall or an older one? I've never received any notice. I did buy my X with very low miles (was a Ford employee's company car) and it may have already been dealt with. I've owned it for 3 years.

it is actually a tsb as in they will fix it for free if you tell them you have the prolblem do a search for 00M12 and you will find more then you need to know

O2 Sensors are merely a messenger.
Replacing them genrally is not the solution.
Some times, yes but not always.