Hello, I recently bought a 1994 SSEI Bonneville from a friend, one owner with 75,000 miles. The car is in immaculate condition, no rust, etc. Live in Minnesota. The previous owner warned me that he had an occaisionally service engine light come on, but rarely. After I bought the car 2 months ago, it would come at random times, at start up, or after driving for 20 minutes or so.There is no rough idling, or any other symptoms, so I have been ignoring this light code. A few weeks ago it came on and I stopped at my local repair shop and had them put on computer, it showed a 1406 code, EGR valve issue. I have read many comments on this issue, but don't know where to start. Again it is not causing any obvious problems, should I just ignore, or can it damage something if I don't start digging in to this problem. I have read some have pulled it and tried cleaning it, some have replaced, etc. Please give me your opinion on what you would do in my place.Have a great day.

Check the tubes for vac leaks first. That can set a code. If nothing, then clean it. You dont want to ignore a light.