My 97 S10 has a check engine light. After reading the codes I have two. P0404 and P0405. Both correspond with an EGR valve problem. I removed my EGR and was going to clean it but couldn't figure out how to take it apart. As far as I can tell the valve is moving freely. I would hate to have to buy another $150 EGR if There is nothing wrong with mine. Could there be something else that could cause this code? any tips/help would be greatly appreciated!