Can someone tell me how many and where (basically) my O2 sensors are on my car? I'm buying an aftermarket module/tune and the programmer is turning off the back two, but I am unsure if I have 1 pre-cat O2 sensor or two. My repair manual is of no help and I've been able to find an underside view of my model car, etc.

2003 Bonneville SE, non-supercharged 3.8 Series/Gen II engine

I want to replace the remaining O2 sensor(s) that will still be functioning with new module/tune, mainly due to this being a used car with 77,000 miles.

I do not use Bosch! Plan on NGK, Denso, or AC Delco/ Delphi

_________________
D.T.

There are two sensors. One pre-cat, which is on the top/center of the rear exhaust manifold. The post cat is in the exhaust behind the cat, hidden by a metal shield.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

Thank you very much Archon!

_________________
D.T.