Reving not right

1) Car starts and idles like a dream....as good as
the day is rolled off the factory floor.
2) Until I rev it above 3500 or so RPM...then it feels
like its missing and has no power. I can keep it
running by playing with the air pedal(gas pedal).
3) After about 1 or 2 minutes it settles down again
and idles perfectly.
4) during the 1 or 2 minutes its running bad the
evac sensor will click loud
5) during the 1 or 2 minutes it will not rev up very
good at all....maybe 3000 rpm
6) after the 1 or 2 minutes the clicking stops and
idle is perfect again, I will be able to rev to 5000
rpm easy but with in a couple seconds it will start
to miss and try to die again.