kevinj45

I just pulled a code 172 out of my 95 GT. Is says front side HEGO, which I have discovered is the O2 sensor. I called the parts store, they say I have 4 O2 sensors in this car, two in front of the converters, two behind. I have been running O/R pipes for 4 years. I was told the two front sensors will be located in the headers, but there are none there. I only have two sensors, but they tell me I have 4. What the hell is going on here? Which one do I need to replace? I can do them both, but do I buy the front sensors or the rear?

Monch

do you have stock headers/manifolds? check infront of the cats if they are not on the headers.

IF the code/check engine light JUST came on, it sounds like your front sensor is bad. This assumes a few things, first that you are using mil-eliminators on the back pair of sensors AND that the problem just started - not that you've just now noticed it - but in fact that it just started.

save yourself some trouble in diagnosing and just replace all the sensors.

sc94gt

I think your car is the same as my model. We only have 2 O2 sensors, not 4.
They are located on the H-pipe, not the headers.
You should see the connectors right before the pipes come out of the floor level... before the cats, when you had them.