I recall seeing something a long time back about a stumble or
hesitation when accelerating  at low to medium throttle. I have a 2003
ZTW and have had this problem since it was new. Of course the dealer
could find nothing wrong and said everything was fine when I took it
in about none months back.
    Well I just took it in for the 20000 km service last week and
to my great pleasure the problem disappeared during the hour or so
that they had it. They did not report any replacements or changes, but
the problem is gone. It now runs as smoothly as I always wanted and
expected it to.  It idles so smoothly now (about 700-750 rpm) that it
is easy to forget is is actually running if I don't immediatelly shut
it off after parking. And torque is much more dependable just off
idle. Does anyone in the Ford service business have any idea what they
might have changed that might account for this miracle healing?
    I will call and see if I can get an answer from the dealer and
will report later if I can determine what the cause was. If you have
this problem, do not believe them if they tell you that all Foci are
all like that. It is fixable, for sure. The fix is quick, easy, cheap
and may just be something that is normally done as a part of the
20,000 km service. The difference is like having a different engine.
No more power, but much, much smoother.

Gord Seifert
Chilliwack, BC