Two.
There are two catalytic converters on the 1998 ford explorer.
On the exhaust pipe, lower, possibly near the catalytic converter.
Bank 2 is the drivers side of the engine in your Mercury Mountaineer Sensor 1 is between the engine and the catalytic converter ( upstream ) Sensor 2 is after the catalytic converter ( downstream )
98 mystique has only one cat conveter
On a 1998 Mercury Mountaineer, the oxygen (O2) sensors are located in two main positions: the upstream (pre-catalytic converter) sensors are found on the exhaust manifolds, typically one on each side of the engine, and the downstream (post-catalytic converter) sensors are located after the catalytic converters along the exhaust pipes. To access them, you may need to raise the vehicle for better visibility and reach. Ensure to disconnect the battery before replacing the sensors to avoid any electrical issues.
2
No , the 5.0 liter V8 engine in a 1998 Mercury Mountaineer has ( 1 ) timing CHAIN
How do i change the chain out of my 1998 mercury mountaineer transfer case
Yes
Yes
Look under the vehicle and count them.
There are two catalytic convertors on this model.