How many O2 Sensors are on the stock 98 GT exhaust and are the all the same.

Surely someone out there knows!!!!!

Should be 4. One before the cats on each side and one after the cats on each side. And I think they are different. The ones behind the cat are the same and the ones prior are the same though...I think.

i think its only 2. but im not really sure

There are 4. Two of them read for air/fuel mixture and two read for properly working cats.

There are 4 but IDK if their all the same...

I agree with sprostang.

there are 4 02 sensors....the back two read your air/fuel ratio...thats why MIL eliminators are placed in the rear two when installing an offroad pipe