My service engine soon light has been on for awhile and don't have any reasons for it to be. I hooked it up to a computer awhile back and they said that it was a carbon build up problem. They told just to run some cleaner through it and I did. The light stayed off for a week or two and now it is back on. I don't want to take it to a dealer and get screwed. So I was wondering if anyone had some suggestions. Thanks