Standing directly in front of the vehicle looking toward the windshield:
Front bank - 1-3-5
Rear bank - 2-4-6
cylinder #1 is the first cylinder from the passenger's side on the rear bank.
Distruibutor rotates clockwise on V6 & 4 cylinder. On 4 cylinder the #1 plug is front of engine. On V6 the # 1 plug is located passenger side front of engine.
Cylinder 1 is located in Cylinder Bank One. A V6 or V8 will have 2 banks of cylinders. A 4 cylinder only has 1 bank of cylinders.
Bank 1 is where cylinder #1 is. Sensor 1 is ahead of the converter (usually in the manifold.
firewall 3 - 6 2 - 5 1 - 4 front of Lincoln LS ( V6 )
On the 4 cylinder its at the front of the motor On the V6 its on the passenger side of the motor , front cylinder
firewall 3 - 6 2 - 5 1 - 4 front of Lincoln LS ( V6 )
the number 5 cylinder is the rear cylinder on the driver side 6 5 <---cylinder diagram 4 3 2 1 front of engine
Starting at rear passenger (right) side cylinder: 1 2 3 then at front bank from right 4 5 6
first cylinder on driver side
firewall 3 - 6 2 - 5 1 - 4 front of Lincoln LS ( V6 )
I found out today that it is on the driver's side of the car. This matters when you need to know which bank 1 O2 sensor is talking to you.