Don't forget to clean out the pipe that runs from the EGR to the intake manifold. The EGR valves can be clean and moving freely, but there is often a ton of carbon built up in the pipe. Remove the intake hose, block open the throttle plate, and take a look with a flashlight into the EGR tube. It'll probably be black. I used a snake-type brush (actually a slide cleaning brush for a brass musical instrument) to clean out the pipe. Take a rag and put it in front of the pipe, spray the crap out of it with carb cleaner (make sure you get the stuff that says 'safe for o2 sensors') and use the brush to clean out the pipe. Try and catch the dirty carb cleaner sludge in the rag. After a few passes the EGR should be much cleaner. Put it all back together, and fire ti up. You'll probably get a flashing CEL for a min or two along with rough idling. Once it smooths out, shut it off, disconnect the battery for 30 mins or pull the ECU fuse for the same amount of time, and see if the codes disappear. Since you have an excessive flow code, it may not be the problem per se, but a good idea anyway to keep it from getting too built up inside.