Bank # 1 is the passenger side of the engine
Bank 2 is the drivers side of the engine
Could be as simple as a vacuum leak on bank 1.
Bank 2 is the drivers side of the engine in your Ford Explorer Sensor 2 is after the catalytic converter ( downstream )
Bank 1 is the passenger side of the engine in your Ford Explorer
Bank 2 is the drivers side of the engine on your Ford Explorer Bank 2 / Sensor 1 is in the exhaust manifold or the exhaust pipe before the exhaust enters the catalytic converter
Bank 1 is the passenger side of the engine in your Ford Explorer
On your Ford Explorer Sport , 4.0 EFI : Bank 2 is the drivers side of the engine Sensor 1 would be close to the engine ( it might even be in the outlet of the exhaust manifold ) BEFORE the exhaust enters the catalytic converter
Bank 2 is the drivers side of the engine on your Ford Explorer Sensor 1 is in the exhaust before the catalytic converter ( upstream ) Sensor 2 is in the exhaust after the catalytic converter ( downstream )
The passenger side of the engine
Bank 1 is the passenger side of the engine in your Ford Explorer
bank 2 is the drivers side of the engine on your Ford Explorer ( V6 and V8 )
In a Ford Expedition , Ford Explorer Sport , Ford Explorer : ( bank 2 is the drivers side of the engine , whether it is a V6 or V8 engine )