I was just out cruising in my car, and all of a sudden the check engine light came on on the left side of the steering wheel, and it stayed on, is it an error code? should i disconnect the negative terminal on the battery to reset the ecu?

 

You should check to see which code it is. Get a wire or a paperclip, and in the "diagnosis" box near your battery, jump the TEN and GND terminals. Then turn your key to "on" and count how many long flashes and how many short flashes you get. For example, a code 18 would show a long flash and 8 short flashes. You can search for a better description, or post what code you have.

 

I need help on that too. Sometimes my check engine light comes on then when the car sits for a while it goes away. It comes on when I run the car hard. I changed the O2 sensor a few months ago because of the same reason.
I wouldn't worry too much RZRX7TT 'cuse my car still runs fine, with the light on.

 

It's probably a EGR code as most are but don't take your chances. Do what P'Cola said and you will find out which code it is.

 

I dont understand what do you do with a paper clip? jump the ten and GND terminals? what exactly do i do with the paper clip? i am not clear on what to do, please expand on what you mean, is their a site that shows me how to diagnose check engine lights?

 

It just means to have them touching through the paper clip. Mazda uses a device just like this and they have a handheld device to plug into your ECU.

 

http://www.scuderiaciriani.com/rx7/engine_codes.html
There ya go. That thoroughly explains it.

 

oh so what i do is take a paper clip and touch one side of the paper clip to the ten terminal and the other side of the paper clip to Ged terminal correct? and with that in place i go back and turn the ignition key to the on position and read the codes that flash before me!!!

 

You put one end of the paperclip (or wire) into the TEN terminal,and the other end in to the GND terminal. Then you turn on your key, and count the flashes.