1980 Buick Riviera check engine light

guessing what's wrong doesn't workon computer controlled cars. get a paper clip and go between A & B on the ALDL. It's beneath the steering colum just on the dash. then turn the key on and count the flashes and write them down. it will flash 3 times for each number 1+2=12 and so on. then go on the site here and look upnder trouble code definitions and look under OBD1 for your respective car. Which in your case will be GM. the codes will tell you what to check. But as your car i s an 1980, check for bad vacuum lines or soft ones, they may be giving you the problem....... When you find the problem an dcorrect it just pull the ecm fuse for 30 seconds with the key off. That should reset the computer.......