Check Engine Light!!

Own a 1990 BMW 735iL and having the check engine light come on. Occurs when driving and rpm is above 1500. Once gauge dips below 1500 rpm engine light dissapears. Does anyone know what the cause of the problem is and how i can fix it? If it is serious let me know immediately. Thanks for the help.

The Check Engine light means Mr. Computer has detected a malfunction in the pollution control equipment. You can read the car's fault codes and get an idea as to what Mr. Computer thinks is the problem by doing what is called the "stomp test". Here's a link for this test:
http://www.pelicanparts.com/bmw/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm

Oxygen sensors are probably the most common cause but not the only one. Over time, the cost of the repair will pay for itself in better gas milage, etc.

does it continue when your engine warms up? if not it could be intake manifold gasket or fuel injector seals...they went bad on my motor, but light went off after the car warmed up to operating temperature