Check engine and O2 Sensor

[rickgig]

It's time to ge the truck inspected and I have a couple of questions before I replace a bad O2 sensor.

First off (haven't been under to look yet) how many do we have (pretty sure it's 4) ?

Do I just replace the bad one or should I replace them in pairs?

Brand... does it make a difference (Bosch)?

I had AutoZone put their diagnostic tool on which said drivers side O2 sensor... will it tell me which of the two on the drivers side it is (I didn't ask nor did the guy tell me)?

[L8 APEX]

Their about 50 bucks a piece I wouldn't just throw parts at it. S1 is a front O2, S2 is a rear O2.

[rickgig]

Thanks Terry.

Bosch okay or Ford parts?

[PoorSvtman]

BOSCH are stock on fords i believe.

[rickgig]

I did a search on some of the other sites and someone said they had trouble with Bosch and went with Ford...

I may be wrong but I would imagine OEM parts are more than likely Bosch.