car runs rough and smells like something is burning

you need to get the light checked now. it is indicating an issue. if you ignore the light, it may do more damage. it sounds like you have a missfire and you smell the cat converter. if it is, you may have damages the cat to the point it needs to be replaced. it is very expensive, around 1000-1200. get it checked at a shop, verified and get a bid. Roy