On most Fords, the oxygen sensor is found by locating the number one cylinder in the engine's firing order, says AA1Car.com. The oxygen sensor bank is typically located there.
On most Ford V6 and V8 engine models, the number one cylinder is typically the right front cylinder on the passenger side in a rear-wheel drive car or truck. On Ford front-wheel drive cars or minivans with sideways mounted engines, the number one cylinder is usually located on the back side of the engine on the right side.
Another way to locate the number one cylinder, to locate the oxygen sensor bank, is to look at the ignition system, reports AA1Car.com. On distributorless ignition systems or coil-on-plug ignitions, the plug wires or coils might have lettering or markings that reveal the cylinder numbers.
The oxygen sensor is one of the key sensors in an engine control system. It monitors how much unburned oxygen is in the exhaust as the exhaust leaves the engine. This is a way of gauging the fuel mixture, and it tells the computer how rich (less oxygen) or lean (more oxygen) the mixture is. Factors such as air temperature, engine coolant temperature and engine load can all affect the fuel mixture.