I have a '98 Ram. I have been getting a sporatic check engine light. It came on about 10 months ago (and went out after a few days) and again a few days ago. I determined that the error code showed it was an o2 sensor but it went out by itself within hours. Is the sensor bad or is a wire loose or something. What should I do? Changing the sensor is not as easy as I was told at the parts store. Thanks.

 

Do you remember if the code was for the pre or post cat sensor? Either way, you should check the lower intake gasket if you don't know if it was ever replaced.http://dodgeram.info/tsb/2000/09-05-00.htm

And have the cat checked out.

 

It was the pre cat sensor.

 

You need to check the 2 things I mentioned above. If they have never been checked and/or replaced. They are most likely shot. And btw, it can't hurt to trace the wiring to make sure it's not rubbed or burned through the insulation some where, And there should be fuses in the PDC you can also check.