P0174 indicates the oxygen sensor in bank 2 has detected a lean fuel condition. Bank 2 is usually the opposite side of the #1 cylinder. Usually this code is seen in conjunction with P0171, which indicates Bank 1 is lean. Lean fuel condition means the fuel mixture contains too much oxygen and not enough fuel to promote efficient combustion; the ratio of 14.7:1 (air/fuel) is not present.
Out first recommendation would be to inspect the MAF (Mass Air Flow) sensor for proper operation. The MAF sensor will collect dirt and dust over time and should be cleaned, if not replaced. If you have the proper diagnostic equipment you may be able to diagnose your Ford Thunderbird MAF sensor at home before buying a replacement. Or else, try cleaning the component (only with electronic circuit cleaner).
While working on the MAF sensor also ensure there aren't any vacuum leaks downstream the MAF sensor. Downstream means AFTER the MAF sensor; once the MAF sensor has detected a certain amount of air entering the intake manifold and it sends this data to the ECU, no additional air must enter the intake manifold or else a lean fuel condition will be created.
Components which may cause inadequate fuel delivery should be inspected as well, such as the fuel filter, fuel pump, fuel pressure, and possible fuel injectors (for clogging).
posted by SmogTips Support
