check engine light on on my 88 caprice i used multiple diagnostic machines and none of them were able to read the computer what can it be????

Try to take a paper clip and bend it out of shape so you have 2 pointed ends. find the 2 upper right pins on the DLC. Stick the modified paper clip into those 2 pins. With the key on engine off you will see the engine light flashing. The flashes are the code numbers. It will always flash code 12 which means it is in diagnostic mode, it really means nothing. It will flash code 12 twice, after that it will then flash the trouble code of your car. you can go online put the gm code number in and find out what it means. If this does not work then I suspect you have a bad computer

If the paper trick doesn't work then try scanning it with an OBDI specific scan tool. Chances are the other scanners where OBDII only or required an adapter to scan an OBDI vehicle.

just the light coming on, but no "REAL ISSUES"? ignore it. mine comes on any time I idle for several minutes, like at a drive thru or a long stop light. then it goes out once I'm in motion again.