i know nothing about how to change them or how often. i got a 50 buck gift card to oriely's. i have 188 000 miles so i know its due. and car has a check engine light on so that might be what it is.

so they are on the y pipe i think and one on each side? are they hard to change? and how much am i looking at spending. pics would be awesome thanks

 

get the code read first. dont assume.

 

even if it has 188000 on the stock ones? so it will always throw a code?

 

If they are infact the stock ones at those miles, then you might want to replace them. Over normal use, debris and things get cooked onto them (soot). It can then mess with readings.

They throw a code once they are completely bad as in don't give a reasonable reading at all.

I changed mine on my car with 120k miles, one of my post cat o2s was giving errors so i just figured the front ones are probably bad if that one was. Changed them and i noticed a slight difference.

They are kind of hard to replace. You just remove the old one and insert new one. ~50$ each at gmpartsdirect, btw you dont need to change the post cat o2s, (i don't think you have them anyways ina 94)

Hit me up on aim, i bought the kappas from you, ill give you more information if you need it.

 

how many pre cat are there?

 

If you get under the car, you will see the sensors up a bit and in front of the cats. They come out like spark plugs. Be careful with the lead wires.

As for price, I'll guess your $50 gift certificate will probably buy you one of the two. The very cheapest I've seen them is $20 for my son's Grand Am.

It would be good to get a scan on your computer but I realize that in itself is another expense. Autozone can't read OBDI ALDLs. At least that is how it went with me the last time I tried. I'm not sure of the years but there is a method where you can get the SES light to flash the DLCs. If the 94 allows this, you can find the fault code(s) and do a google search to see if your O2s are truly faulty.

good luck to you.

 

thanks man

 

Stick with AC Delco O2 sensors; a lot of people have had trouble using other brands.

You have 2 sensors, one for each exhaust down pipe.