2003 ford Taurus--Revving while braking

Back in January, I was driving home and had an issue of my car revving up while I
was pushing the brake down.  Took it to my usual mechanic....he said a couple of
hoses were old and cracked and i needed a new PCV valve and IAC valve.  Things
were fine for a month.  then it did it again....so I took it back and he replaced a couple
more hoses and the intake manifold gasket and said it was good to go.  
Again....one month later (to the day), the same revving issue popped up.  He checked
everything again and said couldn't see anything wrong with it but he did replace the
PCV valve again.  Before I even picked the car up, he had to replace the PCV valve a
third time cause it acted up on him.  
His third PCV valve he said he got from a completely different maker and vendor and it
was fine for the last 4 months of so.  Of course, I'm here today because it acted up on
me again today.  
Now, by acting up, I mean I hit the brake and the RPM's got from 1500 to over 4500
and (obviously) the car doesn't slow down.  Back in January when it first happened, I
could let off the brake and reapply and the car would slow normally but as the problem
has reappeared it's gotten harder and harder to stop.  Once, even having to slam it into
park to keep from going into a busy intersection.   Throwing it in neutral just makes the
engine rev even higher so that option is out.   
I plan on talking with my guy for a long time tomorrow to figure this out.  If he is going
to throw his hands in the air I guess i will check the dealer out.  any suggestions I can
throw his way of things to check/look for????  other than this the car is in great shape
and I only drive 15 miles a day to work in it so i need another year or two max from
this car.  it has no other issues at the moment.