Where is 02 senser on 03 Ford F-250 5.4 liter Triton engine?

On a 2003 Ford F-250 with a 5.4-liter Triton engine, the O2 sensors are located in the exhaust system. There are typically two upstream (pre-catalytic converter) O2 sensors, one on each bank of the engine, and two downstream (post-catalytic converter) sensors. The upstream sensors are generally mounted on the exhaust manifold or just below it, while the downstream sensors are positioned further along the exhaust pipe after the catalytic converters.