Upstream and Downstream Oxygen sensors

[red ink]

What is the difference? Im trying to buy some on the internet and there are two different types for 5.0L mustangs

 

[HISSIN50]

We have only 2 O2's total. OBD-II V8's (read 96+ GT's) have 4.

I suppose ours would be considered upstream (downstream would be toward the mufflers IMHO, and those would be the OBD-II specific lambdas for monitoring the catalyzation process).

 

[red ink]

thank u sir :SNSign:

 

[HISSIN50]

I would confirm that you are looking at the correct ones before ordering (or before they ship atleast) since my logic might be totally flawed.

I do know what you are talking about though (I have looked them up and seen the same thing).

FWIW, quite a few guys on here order them online and they have posted the correct part numbers if you feel like searching old threads.

BTW, I am not sir.

 

[Slow5.0]

94-95 have only 2 O2s
Ours are upstream because its before cats
4.6 (96up) use 4 O2s two upstream before cats and two downstream after cats