I assume the valve was sticking open then? Not sure which head is on your Focus but there is a Ford blanking plate for the EGR as they removed it from later Duratecs. You would still get the warning light though
http://www.burtonpower.com/egr-blank...-i4-fd180.html

Alternatively I removed the recirculation pipe behind the inlet manifold on my 2.0 Fiesta and blanked it off using an M22 sump drain plug, and no warning light.
I wasn't having any issues was just fitting a different manifold that doesn't accommodate an EGR.
The downside is having to remove the manifold.