Contour Enthusiasts Group Archives Forums General Troubleshooting o2 sensor

I have 95 contour. Check engine light goes on intermittently and car seems like it lacks power in terms of acceleration. A mechanic told me that my fuel mix is "light" and that I may need new O2 sensor. In 95 model there is only 1 O2 sensor. is it likely that it is O2 sensor? Is the O2 sensor on exhaust and approximately how far from the front of the exhaust system is it located. Is it something I can do myself? I have 130,000 km on my car.

Thanks..

zetec (4cyl) or duratec (6cyl)??? it's easy to do, atleast on a zetec. click for inexpensive o2 sensors got mine from there.

sORRY...fOrgot to mention it is a Ztec 2L. Anyone have instructions on how to replace the O2 sensor. also is mass airflow sensor and O2 sensor the same thing?

MAF (Mass Air Flow) measures the air coming into the engine. It's attached to the intake after the air filter and before the throttle body.

O2 (or more correctly, "Heated Exhaust Gas Oxygen Sensor" - HEGO Sensor) measures the oxygen in the exhaust in order to determine the amount of fuel to inject in the engine.

If the mechanic read codes from your engine and used that to determine that your fuel mix is "light", then he is probably correct that your O2 sensor needs replacing.

It's pretty easy, with a socket wrench and a special socket with a slot in the side for the wiring. You could also do it with an adjustable wrench or open end wrench (7/8" or 22mm IIRC) if there is enough clearance. Just make sure to spray some penetrating oil on the sensor threads before attempting removal (I recommend PB Blaster), and use some anti-sieze on the threads of the new sensor (most come with a small packet in the box).

Also, VERY IMPORTANTLY, do this when everything is cold. The sensor is heated to a very high temperature when the engine is running.

How do i find the O2 sensor? approximately where is it located?

Does replacing O2 sensor have any impact in temperature of the engine. Mine gauge reads about 3/4 up the normal range and I also need to replace the O2 sensor. I wonder if replacing O2 will have any impact on temp of engine such that the gauge may read 1/2 or 2/3 of the way up the normal.