The oxygen sensor for bank 1 sensor 1 for a 2000 mercury mountaineer is on the cylinder #1 side.
Bank 1 is the passenger side of the engine in a Mercury Mountaineer ( V6 + V8 ) Sensor 2 is after the catalytic converter ( downstream )
Bank 1 is the passenger side of the engine in your Mercury Mountaineer Sensor 1 would be close to the engine before the exhaust enters the catalytic converter ( upstream sensor )
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 )
Bank 2 is the drivers side of the engine in your Mercury Mountaineer ( V6 + V8 ) Sensor 1 is in the exhaust close to the engine before the exhaust enters the catalytic converter
Bank 1 is the passenger side of your engine Sensor 2 is in the exhaust after it passes through the catalytic converter ( downstream )
location bank 1 sensor 1
On a 2002 Mercury Mountaineer ( V6 and V8 engines ) Bank 2 is the drivers side of the engine Sensor 1 would be close to the engine BEFORE the exhaust enters the catalytic converter
Bank 2 is the drivers side of the engine sensor 1 is in the exhaust , close to the engine , before the exhaust passes through the catalytic converter
There are 4 O2 sensors in 1999 suburban.Bank 1 sensor 1, bank 1 sensor 2 on the driver side before Catalytic Convertor. Bank 2 sensor 1 on exhaust Manifold, passenger side. Bank 1 sensor 3 is after catalytic convertor.
Try to picture this Bank 1 Sensor 1 Bank 2 Sensor 1 Catalytic Conv. Catalytic Conv. Bank 1 Sensor 2 Bank 2 Sensor 2
p134