There seems to be a lot of confusion as to which O2 sensor goes onto a fed spec, even on Canadian sites.

Does a 00' Fed spec have 2-3 wire O2's and 1-4 wire? Or 2 4-wire and 1 3-wire?

I'm pretty sure the 4 wire is the rear but there is confusion with the front when ordering.

 

Fed spec cars use two 3-wire and one 4-wire O2 sensors.

The sensors that monitor the gas coming out of the exhaust manifold are the 3-wire ones and are referred to as "upstream" sensors. The one after the catalytic converter is the 4-wire sensor and is referred to as the "downstream" sensor.

 

Thats what I thought. Thanks for confirming.

 

Can a malfunctioning Bank 1 Sensor 1 trick the computer into thinking that Bank 1 is running lean ? Thereby the computer dumps in more fuel...messing up the idle when hot ?