Bank one is the driver side.
right bank, rear cylinder
The side with cylinder #2, the pass side.
Trouble code P0420 means: Catalyst Efficiency Below Normal (Bank 1)
The question is a little confusing.Please try to be less wordy,but more precise.Thanks
bank 2 is closer to the firewall
bank 2 is the drivers side of the engine
Bank 1 is the passenger side of the engine and bank 2 is the drivers side of the engine on your 1997 Mercury Mountaineer 5.0 liter V8 engine
bank 1 is the passenger side of the engine
Bank 1 is the passenger side of the engine on a Ford V8 and V6
Bank 2 is the drivers side of the engine on your Ford F-250 5.4
Bank 2 is the drivers side of your 4.2 liter V6 engine in a 2005 Ford F-150
That would be the passenger side of your Ford 4.0 liter V6 engine ( also called bank 1 )