1994 Mercury Cougar • 114,000 miles

I read the codes and it is telling me that the O2 sensors are bad. Can you tell me how many there are, where they are located, and can they be tested?
January 9, 2013.

What engine?

Jan 9, 2013.
Don't mean to butt in, but I was already looking up info for this. The 3.8L shows two 02 sensors. The 4.6L shows 4 02 sensors. They are in the exhaust. The code number should tell you which o2 sensor. The code doesn't tell you what to replace just that the system thinks there is a problem on that circuit.

Jan 9, 2013.
Its the 4.6 liter v8, I had just got back from the autoparts store and had them test it as well. They told me that it is reading a code for a bad o2 sensor and that it has 2 sensors. One up or on the exhaust manifold and the other back past the castletic converter on the exhaust pipe. Then they proceeded to tell me they cant tell which on is bad and that I should replace both. The front one is about 80 Dollars and the rear just other 100 Dollars. Not what I wanted to hear.
Any thoughts or ideas as to what I should do.

Jan 9, 2013.
I just posted what my database showed. Databases are not always correct. Count the 02 sensors in the exhaust. I looked at 02 sensor price for your vehicle At autopartswarehouse. Com

Universal 02 sensor around 35 dollars not including tax, price for one. You will have to make wiring connections with that sensor. Can't comment on quality, don't know.

One partsbook showed two 02 sensors required for 4.6, before the cat, nothing after. Usually a sensor after the cat is for obd2. I'd have to visually look at the vehicle and count the 02 sensors in the exhaust.

Jan 9, 2013.