My check engine light came on recently, but the car still runs fine. It has 84K on it, and bought it with 65K. Did a tuneup yesterday, but, the light is still on. One day though, the light came on, stayed on for a few days, and then it went off. Then, it came back on again. Is it a bad O2 sensor? Where is the O2 sensor, and what does it look like? Any help you guys could give would be much appreciated. Do I need to go to a dealer to have the code read? Thanks for any help you can give.

 

You could check the ECU code yourself if you feel comfortable. I've never actually done it, but I think either Maximadriver.com or the MaxFAQ has the instructions. I have no experience with O2 sensors myself so I can't help ya.
Sorry
-hype

 

and get the mil code and post back with the answer/result and we will go from there. Do a search if needed for the way to pull codes.

 

The Check Engine Light is evidence that something is wrong. That
"something" may be any number of things, some major and some minor. It
might be nothing more than a loose fuel filler cap. The Engine Control
Module (the computer) detected a problem and turned on the Check Engine
Light. At the same time it stored one or more Diagnostic Trouble Codes.
Get someone to do a DTC readout for you. This is not a big deal, does not
require specialized "dealer only" test equipment, and should take less than
an hour. When you know the stored DTCs, you will have a fair idea of what
repairs are needed.

If you like to do your own "wrenching" you can do the DTC readout for
yourself. Go to your public library and borrow a Chilton's or Haynes
manual for your vehicle. It contains detailed instructions and a table
which "translates" the numerical codes into words. No special tools are
required.

You will also find instructions to do a DTC readout and reset
the Check Engine light at:
http://vbxmaxima.8m.com/ecu.html

The DTC "translations" are found at:
http://vbxmaxima.8m.com/ecudecoder.html