Oxygen Sensor Replacement

I have a friend with a 2003 Taurus 3.0 Flex Fuel. The O2 sensor is bad (Code P0133, Sensor CKT slow response Bank 1 Sensor 1). I haven't seen her car yet but want to get an idea if I can fix it or not. Where is the O2 sensor on that car? and does that code sound like the sensor is bad or the circuit?

Code P0133 is usually a sensor. The sensor you're after is located on teh right bank (the one closest to the firewall) and is in the exhaust above the catalytic convertor, there's two and one is downstream from the cat. The sensor swap is pretty simple, but you will probably want to invest in an O2 sensor socket if you haven't already, it makes the job go much smoother than trying to wedge a 7/8 wrench up there. Good luck with it.

can I get to it from up top or do I have to go underneath?

if you dont mind me asking how much is this gonna cost total?

I looked on line and find O2 sensors run fifty to sixty bucks.

AutoZone sells the Great Neck Oxygen Sensor Wrench Set #27110.
A comprehensive user review follows:
"This has got to be one of the best specialty tool deals I've ever seen. At $15.00, even with shipping added, you can't lose. Consider: Even if you drive your vehicle "until the wheels fall off," you will probably not change the O2 sensor more than once or twice. The first time you do--the first time you venture to try doing it yourself--you are almost sure to find: that a mere 22mm open-end wrench just can't be fit in over the sensor's wrench flats (say, if your sensor intalls in the crossover); and that a box wrench will not fit over the connector even if it is the right size; or that when you go looking for a 22mm split-type box wrench that will slip over the wires, finding that wrench in the 22mm size is difficult to impossible. Then, you are faced with finding the specific tool that will work with your particular vehicle; and paying $35 or more (even $100 or more) for that single application tool. But what if you change vehicles?...then there's a good chance your pricey tool will no longer be suited. With the #27110 set, however, you are almost certain to have universality that will adapt to just about any application; those few owners who might not would, more likely than not, be the ones who would not do the work themselves anyway. Now what are the features that make this a superlative value? Consider adaptability. Start with the one thing that could be seen as a drawback: that you will have to provide your own solid, sliding, or ratchet-type socket wrench handle--but this drawback is really an advantage!! That's right-- Using your own wrench handle, extensions, wobble extensions, ujoints, etc.,...your ability to fit the tool despite any restriction is limited only by the standard socket wrench accessories you have on hand, or can readily purchase.

How about drive size and shape? You're covered there, too: the fittings will accept both 3/8" and 1/2" socket drives; and the 1/2"-drive socket will accept the wrench handle's drive in any one of eight orientations--in case your 1/2" wrench handle is a fixed rather than ratchet-ing type.

The kit comes with one, chrome plated, 3/8"-drive deep socket which is slotted on the side to slip over the sensor wires--looks much like a spark plug wrench. If that doesn't suit (say, if your sensor is too long to prevent pinching of the sensor wires sticking out through the slot) you still have a choice between two "crow's foot" type sockets: the 3/8"-drive and/or the 1/2"-drive. On each of these, the slot (for the sensor wire harness) extends the entire length of the socket; so the socket can be slipped over the wire--and the wire cannot be pinched--no matter what. Purchased individually (if you could find them), any one of the set's sockets, even at wholesale, would likely cost as much as or more than other, single purpose tools (even at retail)...so even if you only use one socket from the kit, you're still ahead. Figure a minimum of $10 to $15 (wholesale) for each of the sockets; then add, say, $8 for the case...and you have a tool kit that could be expected to retail for at least $40, probably much more. Now consider what three separate, single purpose wrenches would cost at $35-$75 each. So whether it's brand new or used, this is a tool deal you're not likely to beat. In effect, you are getting the large-volume purchasing power (and control of price) normally only available to the big outlets--the Walmarts, Home Depots, Auto Zones and such--but you only have to purchase one item. It's also a deal in which buying your own will not cost you much more, if any, than receiving a loaner for "free"--especially when you figure in the cost of picking up and returning a loaner.
Conclusion: Highly recommended."