Just called the Dealer to get a price on an 02 sensor. He told me there was two different ones. I wanted the front but he said no, the front has two different ones it could be, depending on the air flow.

In order to get the right one, he needs the VIN.

I've never heard of such a thing. Is anyone familiar with this?

On the '97 model with SII 3800 the dealer is correct and there are two different front 02 sensors for that year.

AC Delco PN: AFS109 with RPO LESABRE TIMING (WA2)
AC Delco PN: AFS75 without Without RPO LESABRE TIMING (WA2)

Thank you for the reply. Do you know why the same motor, same year have different ones?

Chris.

Probably just production overlap since GM revised some odb-ii emissions parameters. The AFS75 is the old 02 sensor used in the Series I Vin "L" 3800. From '98 to at least '03 models GM starting using the AFS109 as standard. '97 is the only year affected where there were two different ones possible.

OK, thanks. Here we go again. I went to get a LIM gasket. They have two different ones for 97. No way to know until I get it apart witch one it is.

My friend told me to get the 02 sensor from the dealer. What about a Bosch?
Chris.

On the LIM gaskets there is the pinned and unpinned end pieces. Normally you will not know which one for sure until disassembly.

I agree with your friend in part but I would get them through another AC Delco source since dealers charge more. Although some people claim to have good luck with the Bosch 02 sensors I would pass on them. Also, claims of poor gas mileage compared to the GM/AC Delco ones.

Good luck!

My car barley runs. I've cleared the code and just drove it a few times. It's finally running rough.
I can't wait to get it online. $50 more at the dealer.

The O2 sensor is basically the same, the plugs are different. Notice that one has a flat 4-wire plug and the other has a square 4-wire plug. Look at the connector to identify what you have.

http://img129.imageshack.us/img129/3503/acdelcopartafs752531218pq4.jpg

http://img129.imageshack.us/img129/8076/afs109withlesabretimingns6.jpg

Wow!! Changed the 02 Sensor. Car hasn't run this good in a long time! Everything, acceleration, idol, running, everything is powerful, smoth.

I think I'll start doing 02 sensors with plug replacements. Maybe every other time.

Thanks for the replys,
Chris.