Oxygen O2 Sensors?

[mech engineer]

1. How many O2 sensors are there in a 2000 Boxster?
2. Do they come in pairs or singular when replaced?
3. If CEL indicates one is bad, can it be determined which one specifically?
4. If CEL indicates one is bad, should I replace just the bad one or all of them?
5. I have driven car and there doesnt appear to be any performance issues; Can the boxster perform normally with bad O2 sensor?


Thanks!

2000 Boxster 36000 miles

[Rodger]

1. My 2000 S has four, one prior to each pair of cats and one after each pair. So, two per side.
2. They are sold as single units.
3. Normally the fault code downloaded from the DME is very specific about which O2 sensor is out of range.
4. Some people say to repalce al four at once, others just do one at a time for reasons of cost. I would start with one, and if it doesn't fix the problem, at least you didn't buy three sensors you didn't need.
5. The Boxster can perform fine with a bad sensor, but you could damage the catalyst on that side if the engine runs too rich on that bank. Catalysts are not cheap to replace! And who wants to stare at a check engine light all day???? Not me....

[mech engineer]

Thanks! I appreciate the advice.. two more question though...

1. What is the typical life expectancy of these O2 sensors?
2. What is the typical life expectancy of the MAF sensor?

[Wonko The Sane]

I'm battling this right now.. MnBoxster has a wicked write up on them here: http://986forum.com/forums/showthread.php?t=4902&highlight=oxygen+sensors

Granted, this is MUCH more than you really wanted to know about them, but take a read, it's good to know what's happening inside your car.

My take: Replace all four. They work as a set, and if one is going out of spec, they all will be shortly, as they've all been subjected to the same exhaust heats and chemicals.

According to Bosch (according to Jim's post, above), the O2 sensors are supposed to be replaced every 60k (for our heated ones).

As for the MAF, from what I've read, it's been "When it breaks'

Cheers!