Need help with which oxygen sensor to get

[makavelius]

Hi:

Have a 99 camaro. I believe my car has 3 oxygen sensors. I need to change the two front ones or the two before the cat. I was going to order the ACDELCos but I don't understand the listing that I see so I need help in figuring out which ones to get. This is what I see listed for ACDelco for the camaro:

Item #1
HEATED OXYGEN SENSOR (POSITION 1)
Note: in exhaust manifold; 4-speed at (m30); 5-speed mt (m49); except non-heated o2 sen (abn)

Item #2
OXYGEN OEM SENSOR-SENSOR (POSITION 1)
Note: in exhaust manifold; non-heated o2 sen (abn)

Item #1 seems to be about $70 and item #2 is about 45 dollars. My question is do I get one of each to replace the front 2? I don't quite understand what the difference between the two is. By the way I have an automatic transmission.

Thanks for any help.
Regards
HR

[00firebird]

#2 sounds more stock and #1 seems like a upgrade? just guessing, i dont know any more than yo udo

[FunkZ]

Look at your existing sensors and count the # of wires. Most ODB-II cars use "pre-heated" 3-wire O2 sensors, whereas most ODB-I cars use the older single-wire O2 sensors.

Of course, the heated 3-wire sensors are twice as expensive as the older style.

Only difference I'm aware of is that the older single-wire sensors are not very accurate when cold, thus the 3-wire sensors were designed with a power and ground wire to pre-heat the tip to provide less emissions on engine start-up.

[F1GT]

The more expensive one is the one you should get. I bought Bosch several months ago, about to install them soon.... and it cost me ~70 bucks too.

[ellik]

correct. you will need two of the #1's. 3 wire heated O2 sensor. About $70 a piece.

I dont know what the #2's are for. They ARE NOT the base version with #1's as an upgrade.

[makavelius]

Ok great thanks again everyone for your help. I'll get two of the #1s.

[FunkZ]

#2 is the non-heated (aka single-wire) O2 sensor that I would purchase for my car for example - ODB-I. I only paid $20 each for the Bosche version at Advance, but Delco's are a bit more expensive.

Having a '99 you need the 3-wire pre-heated sensors.