I've gotten a few P0400 CEL's in the past couple of weeks. I had some earlier in the winter, so removed and cleaned the EGR valve with carb cleaner as best I could.
It came back, so I just swapped everything with the known good parts from the Flea.
It sure idles smoother and runs better at low RPM than it used to!
I busted the wee hose fitting off one of the electro-valve actuator thingers. It may have been cracked all along, so there would have been a very small vacuum leak. Or it's a coincidence and the prob is elsewhere. Who knows!
I'll swap the components back one at a time and see what happens.