redline problems
 

I think this is in the wrong section but oh well. I drive an 04 redline and it has the p0171 code that will not allow me to pass inspection, the dealership has tried cleaning the throttle body, replacing the mass air flow sensor and now tomorrow they are going to try a new boost bypass valve, to me i think it could be a faulty o2 sensor or possibly something to do with the fuel system it self can anyone speak on this problem the p0171 code states Fuel Trim System Lean ECM