On a 1999 Ford E-150 :
For the GASOLINE engines ( V6 , V8 ,, V10 )
Bank 1 is the passenger side of the engine and bank 2 is the drivers side
The passenger side
On some E150 it is located under the dash on the drivers side. On 2003s it is located in the left (drivers side) quarter panel below the window, near the drivers side door frame.
It is located on the Left Side ( facing the engine) by the Alternator.
Its located behind the air cleaner housing assembly. You would have to remove that first, and it should be to the right side of the intake manifold, just a little lower.
on the drivers side on the trans.
On a 1999 Ford Crown Victoria : Bank 1 is the passenger side of the engine Bank 2 is the drivers side of the engine
The bank 2, Oxygen sensor 2, on a 1999 Mitsubishi Diamante is located on the passenger side of the vehicle. It is in the exhaust in the undercarriage.
Bank 2 Sensor 1 located downstream left front rear side.
On a 1999 Ford Explorer : Bank 1 is the passenger side of the engine ( 4.0 EFI / 4.0 SOHC / 5.0 V8 )
fuses are located drivers side near steering column & some are located dr. side , middle of van in floor level compartments.
Bank 1 is the passenger side of the engine in your E-150 Sensor 1 is between the engine and the catalytic converter ( upstream sensor )
on the side of engine that #1 spark plug is located.