Two but the upper would be the one to cause problems
A 2001 Ford Explorer Sport , with the 4.0 liter Single Over Head Cam V6 engine should have ( 4 oxygen sensors )
The 4.0 liter OHV engine has ( 3 ) The 4.0 liter SOHC engine has ( 4 ) The front ( 2 ) oxygen sensors are used in the adjustment of the engine air / fuel ratio
one upstream and one down stream on in the manifold up stream the one in or behind the converter down stream
There are 2 oxygen sensors.
The computer will vary it from 600-1200
On a 1998 Ford Explorer Sport : If it has the 4.0 litre EFI engine ( which is an over head valve / pushrod design engine / the 8th character of the VIN is an " X " ) there are ( 3 oxygen sensors ) If it has the 4.0 litre SOHC engine ( the 8th character of the VIN is an " E " ) there are ( 4 oxygen sensors )
There are four o2 sensors on a montero sport.
It has two oxygen sensors. One at the front of the catalytic converter and one after it.
it is located in the distributor base. look above/right of the oil filter. for a 4 liter engine
They are 43 Ft. lbs
Check the oxygen sensor. My 1995 Grand Cherokee stopped stalling while driving after it was replaced.
Both oxygen sensors are in the exhaust pipe, one under the front of the engine, one roughly under the passenger seat are.