1999 Oldsmobile Intrigue

1999 Oldsmobile Intrigue 6 cyl Two Wheel Drive

I am replaceing the cat converter and the O2 sensors the rear O2 sensor is no problem I have a direct fit so am replaceing it from exaust manifold to the exaust where is the pre O2 sensor it is not located on the pipe which is what everyone keeps telling me I have cat con off and was not on the old and no place on the new but they swear it has one
February 25, 2010.

#1 is in the right side of the exhaust manifold and #2 is in the exhaust system behind the catalytic converter. If its not there then someone may have had exhaust work done on it previously and never replaced that sensor.

Feb 25, 2010.