Well after 48000 miles the check engine light came on. I borrowed an OBD 2 scanner and got the code P0401 " insufficient EGR flow detected". I'm going to start going thru the system tomorrow. Wires, vacume lines, ect. Seems like there could be quite a few things that could induce this code. Any suggestions on a troubleshooting routine or path to take as I start. Like first this, then this, then this. Many thanks. Mark S.