Subject: mitsubishi mighty max 1992
Question: what reasons does the check engine light come on and stay on?
Answer: Wayne,
Your check engine light comes on when your car's computer picks up a bad signal from one of your sensors. The most common sensors to cause this are your fuel and intake air sensors. Make sure all of your connections under your hood (at least the ones you can see) are tight. Check your gas cap to make sure it's screwed on tighly. A loose gas cap can result in lower fuel pressure, which can trip a sensor.

If everything looks fine, you will most likely have to bring your car to a mechanic, or even the dealership if no local mechanic has a code reader. Another potential problem could be with your car's computer itself. Read this web page for further information:
http://90gsx.com/eclipse/cap/caps.htm

If your module is faulty, you will see all sorts of strange readings.
Good luck!