Will an O2 sensor off a 6-cylinder Ford fit and work on 5.4-liter engine?

It is unlikely that an oxygen (O2) sensor from a 6-cylinder Ford will be a direct fit or function properly on a 5.4-liter Ford engine. While both may be Ford vehicles, the O2 sensor components, such as thread size, electrical connectors, and sensor specifications, may vary between different engine types and models.

It's essential to use the correct O2 sensor designed specifically for the 5.4-liter engine to ensure accurate readings and proper functioning of the vehicle's emissions control system. Using an incompatible O2 sensor can potentially cause issues with engine performance, fuel efficiency, and emission compliance.

You can consult the vehicle's owner's manual or check with a trusted auto parts store or Ford dealership to obtain the correct O2 sensor for your 5.4-liter engine.