I ran the codes from the check engine light and found: P0401: EGR flow insufficient and P0720: Output speed sensor circuit malfunction. The question I have is whether or not the EGR valve is bad or the hose is clogged? Second, I am a little confused because the book says there is a VSS (vehicle speed sensor) and a Crankshaft/Engine speed sensor. Which one is causing the code? I would assume that the Engine speed sensor is the culprit but I am not sure. Any help is much appreciated.