You have one in each of the exhaust manifolds. it might be on the cross-over pipe behind the engin
motorcraft . com just shows ( 1 ) oxygen sensor for all available engines in a 1991 Ford Ranger
I'm not a mechanic / technician but on a 1988 Ford Ranger there might be ( 1 ) oxygen sensor ( upstream sensor )
On the firewall on the pass side.
you can breath
the o2 sensor is located on the exaust manifold
The O2 sensor after the catalytic converter.
It just has ( 1 ) oxygen sensor , before the catalytic converter ( upstream )
Where is the ford ranger 2004 revcounter sensor conected
There are 2 heated exhaust gas oxygen sensors , 1 screwed into the outlet on each exhaust manifold on a 1993 Ford Ranger 4.0 L .
On a Ford Ranger ( V6 engine ) Bank 2 is the drivers side of the engine Sensor 1 would be close to the engine before the exhaust enters the catalytic converter
There is one in the exhaust system before the catalytic converter and sometimes one after it.
in the exhaust pipes behind & in front of converters