Service engine soon light

this “idiot” light has been on in my vehicle for over 2 years. it would go on and off for a while (tried new gas cap)but has now been on steady for over a year. i have had in numerous garages and told many different things, the latest being the crank shaft sensor. it has been put in 3 different garages and it would stay off for a week then return. i am also burning oil (not leaking, but have to add 1 quart per month) i have been told not to worry unless it starts flashing (right now its a steady light) do I need to worry? any suggestions to what it might be? i would appreciate any suggestions.

You need to take charge of the situation by finding out for yourself what code(s) are present on this Olds of unknown vintage and unknown odometer mileage.

Take it to Auto Zone, Advance Auto, O’Reilly, Napa or other auto parts retailer for a free scan of the stored trouble code(s) and come back here to report the codes. Once you and we know the codes, then some focused guesswork can begin. Until the codes are a known quantity, all of our long-distance guesswork will consist of only Wild A** Guesses (WAGs).

IT’S A 1999 AND HAS 121,000 MILES. THANKS FOR YOUR RESPONSE, I WILL TRY THAT. DO YOU KNOW IF THERE IS A CHARGE AND HOW LONG THE TESTING TAKES?

Call and see the ones that do it for free.
After you get them to your car it is less than 5 minutes for them to tell you the code.

You’re welcome, but there is no need to SHOUT!

Since it is a '99 model, that means that the car has an OBD2 system, and that is a good thing, since many places can no longer access the codes from an OBD1 system.

There is usually no charge for this service from the retailers that I mentioned.
As to how long it will take, that depends on how busy the store is when you arrive.
If they are not busy, you might be on your way with the codes within 5 minutes of your arrival.

Figure O2 sensor is trashed and catalytic converter is trashed due to running 2 years in limp home mode. This has probably caused phantom codes. It won’t run right without addressing those two things anyway.

Put a piece of black tape over the light and save yourself some time and money. You will not recoup the price of fixing this car in either increased resale value or increased fuel economy.