My check engine light came on this week and then went off by itself. I was curious, so I took it to my local auto repair place to see what the problem was. They said it was the EGR valve and that it needs to be replaced. The quote was $425 because they said they needed to replace the gasket as well. I chose not to have the operation done. Should I go back or is there something I can do myself? I noticed some RTP people on this thread who have dealt with EGR's before. Any advice?