Well, the head gasket replacement seems to have done the trick on mine. No CEL for over a week now and it even passed emissions yesterday so I can get her registered. Contrary to what the independent shop said (which was that I needed a new intake manifold as well as the manifold gasket) it seems like all it needed was the gasket replaced. As I said, the bill was $250, not great but not terrible either (in my case the company that sold the truck to me covered it but if they hadn't, I would have coughed up the $250 myself. Wouldn't have been happy about it but I would have done it.)