I have a 1994 G20. When I first bought the car new in 1994, the check engine light came on. It was under warranty and the oxygen sensor was replaced and fixed the problem. Has anyone else had a problem with the light coming on as I have had at about 80,000 miles? Is it necessary to correct the problem or is it just a minor pollution control device glitch? Is it something I can fix myself. I don't have a diagnostic computer. Thanks.