1991 mighty max check engine lights comes on and off

There is a error code, stored in the cars ECM( ecm means cars computer).You will need to get your car scanned to get this error codes.Once the error code is there, you can get the faulty part replaced, as per the code.--------The check engine light comes ON when the cars computer (the ECU) notices any kind of electrical problem in car. In some cases the check engine light comes on then turns off. In that case the exact error is not getting confirmed so this happens. But once the problem gets confirmed the engine light will remain permanently ON till the problem gets solved. In this case I suggest you to get your car scanned at autozone service center. It's absolutely free. In case in car scanning, if any error code is retrieved then you can check which part is faulty as per the error code. If no error code is retrieved, then you will have to get the battery to starter, battery to alternator connections checked.You will have to get the throttle body and IAc valve cleaned.The IAC valve is located on throttle body.Get this cleaned and it should help.But most probably you will receive a error code.Due to which the check engine light is blinking.---------this should help.Thanks.Helpmech.