An error code P0133 on your Ford vehicle indicates there is an issue with the air fuel ratio in the engine. While this error is unlikely to cause any drivability issues, it may cause problems with emissions testing.
This error refers to the front oxygen sensor on the bank beside your engine's No. 1 cylinder. Seeing this error means the sensor is not adjusting the air fuel ratio, or not addressing it properly.
An error P0133 can be reset on your Ford, and this may cause the error to disappear if it was only a temporary issue. If Error P0133 reappears after reset, your oxygen sensor could be failing. Other possibilities include problems with the wiring running to the sensor, a problem with the mass air flow sensor or an exhaust leak.
Before replacing the oxygen sensor on your Ford, check for inlet air leaks and exhaust leaks. Also, check the wiring to the oxygen sensor. In addition, the operation of both the mass air flow sensor and the oxygen sensor should be checked to determine which is the root of the error before replacing.
