i have a ford escort zx2 2003 model....i have been to two different
dealerships and neither have been able to solve this problem. this
particular model i have is a standard transmission.  When using the
A/C, the throttle seems to stick..or "lock" after i have taken my foot
off the gas....almost as if the cruise control is set to on.  this
only happens when using any mode that the air compressor is on.  as a
result of this, i sparingly use the A/C even when it is very hot
because i am very uncomfortable with the way the use of the A/C makes
the car perform.  the two dealerships informed me that everything has
been checked....and nothing is defective...that it is the way it is
programmed.  I have a hard time believing that but i am out of options
with them as they say nothing is wrong with the car.  Before you
answer saying the throttle needs to be lubricated they did that
also....also...the only time it will finally "idle down" like it is
supposed to is when i engage the clutch.  then it will idle down from
high revolutions to normal.  The Car has performed in this manner
since it was new...i purchased it in november of 2003 and presently it
has only 15,500 miles on it.

I'd suggest test driving an identical car as yours, perhaps a few.  If
they do the same thing then the dealers are right.  Although it
doesn't sound right to me (I used to be a service writer at an
independant repair shop).  One thing that has been helpful for me is
contacting the regional / district manager of the manufacturer.  Trust
me they have better things to do then deal with my nonsense so they've
told the dealer to do whatever to get me off their back.  When the
service writer told me that I knew that I finally found the way to
deal with them.  Good luck, drive safely!

I searched through some forums and it seems there is a problem with
the "Throttle Position Sensor" on many Escorts.

Thanks to both of you for your comments... :)  yes...i thought i would
try to test an identical car....thing is...it was late in the year
when i bought the 2003 model...and there were only a few on hand
afterwards and those disappeared quite quickly too because of a large
manufacturers discount (rebate) they had on the ZX2's. so by the time
i found out about the problem....there were no cars like that left at
ANY of the dealerships. i have tried to find people with the same
car...either coming or going in different parking lots to question
them on the performance of their vehicles...but every single one i
have talked to had an automatic.  the closest i could get to a similar
situation was a 2001 owner (automatic transmission though) that told
me sometimes his surged a bit at redlights.

Thanks also for the comment on the Throttle position Sensor....i will
check into that possibility..!!!!... :)  I also had to snicker at the
comment about "told the dealer to do whatever to get me off their
back"....not a bad idea??....LOL

Thanks again.... !!