I got a P0401 code the other day (EGR, insufficient flow). I replaced the EGR valve and reset the codes. The code came back so I had autozone reset the code with a reader to be sure but it came back. My research showed that it can be caused by carbon build up i the tubes so I used a rag to clean out the tubes the best I could. I did notice that the gasket wasn't even with the whole against the manifold and was covering it a bit. Could that cause the insufficient flow error?
