Hi Emily,
There are 4 total O2 sensors on the V6 SVT. Two identical Upstream sensors and two identical Downstream O2 sensors. The "Ups" are positioned before the "pre-cat" built into each exhaust manifold and are VERY important to the running of the engine as they control the air-fuel ratio 99% of the time. The "Downs" are positioned after each "pre-cat" and are less important as they are only used to monitor the effectiveness of the pre-cat. I could be wrong but I do not think they have any effect whatsoever ont the running of the engine. They will however trip a CEL (check engine light)if they start running at a voltage about 30% beyond "normal" and so will the Upstream sensors at about the same point.
Both the sensors you referenced are the important Upstream sensors.
If what you say is true and you have written proof that they billed you for parts and labor for a water pump replacement that was not performed and they don't have a plausible excuse...holy crap...livid would not begin to describe my feelings. I'd be naming names to Ford and the BBB and on this forum. The consuming public, Ford, and especially you don't need that kind of blatant disrespect.
...Ed
