Oxygen senson replaced but still have problems
 

I get the codes...P0171 and P0174 Pnd Mod10 System Too Lean.
I replaced the oxygen sensors (2 upstream 2 downstream) with Bosch parts and codes came back.
My next plan of attack will be
Mass Air Flow Sensor.


Am I on the track? PLEASE HELP

Re: Oxygen senson replaced but still have problems
 

An earlier post (ie the 0ne that refers to 2,200 dollars to replace OX sensors had similar concerns. As have I as well. I was told that I needed to complete a drive cycle before the engine light will go out. It made some sense to me so I am putting miles on it and hoping to see the light go out..Not sure if this was accurate information or not?
Kevin

Re: Oxygen senson replaced but still have problems
 

You had "too lean" showing up on both sides of the engine and you replaced the O2 sensors? Sounds to me like the O2 sensors were simply telling you the truth and that you really ARE running too lean.

As to where to go next, I'd try cleaning the MAF (that is, take it OFF the car and really clean it) and looking for vacuum leaks. I imagine a can of Seafoam would not be a bad idea, either.

Re: Oxygen senson replaced but still have problems
 

I believe that it takes three drive cycles to clear most emissions codes.

Re: Oxygen senson replaced but still have problems
 

You may have to clear the CE light by disconnecting the battery for about ten seconds. Then drive about fifty miles to reset the codes.


PIZZA has it right, Check for vacuum leaks including around the Throttle body.


You can clean the MAF but I find it sometimes needed complete replacement.