depends on the installation. If it uses a crossover pipe to a single exhaust there are three. one in each manifold pipe and one behind the cat convertor. If it is a dual exhaust there will be 4. again one in each manifold pipe and one behind each cat.
There are many sensors on the engine, need to know which one you are looking for.
There are many sensors that can trip the check engine light to come on.
According to the engine wiring schematic in my Chilton book : For a 1999 Ford Ranger , 4.0 liter EFI , V6 engine : ( there are 3 oxygen sensors )
The 2001 Chevrolet Suburban is equipped with one knock sensor. The knock sensor will be attached to the back of the engine.
The 1999 Chevrolet Cavalier 2.2L engine has 115HP
Gas engine has two, diesel has zero.
Two
You need to be more specific as to which one you are referring as there are many all over the engine and accessories.
There are many sensors on the vehicle. Which ones are you looking for?
Assuming you mean O2 sensors, the 2004 Chevrolet Malibu with the 2.2L engine has two O2 sensors, one upstream (before the cat) and one down stream (after the cat).
It depends on which engine you have. Give us more info.
It will depend on the engine size. All will have 1 before the catalytic converter and 1 after each one.