Strange that you should mention that.

This past spring that device and the egr were both replaced.  In that
case the check engine light did come on.  That repair was so
expensive, $500, (@ firestone) that I'll not do that ever again.  As
you might be aware, the cost for both egr parts is like $160 at
autozone.  Firestone was charging double that for the parts and then
exorbitant labor.  You know there is profit at $160, and you can guess
the profit at $320.  I used to go to firestone regularly for repairs
but have moved and the local store act like crooks.  After the repair
I asked about what I should do if the light comes on again.  I
expected to hear: we warranty what we sell.  Instead I got: well, it
would probably be something else we didn't work on.

I had another run-in with firestrone a couple of weeks ago about
rotating my tires (a free service) and once again they acted like
crooks.

Anyhow...

I'm fairly sure that my problem is a fuel filter that is
disintegrating and the pieces are clogging the injectors.  The filter
is original equipment.  Unfortunately it looks like I've munged the
special tool required to release the filter and will have to do some
fuel line cutting and replacing.  I think I'm going to wait for warmer
weather before undertaking.

Thanks for the feedback...