Transmission shift

I have a96 mark8 LSC WITH
only78,120miles on it that I
resently bought from a guy
that got it from an estate sale
the guy who owned it had
pasted away and I think it sat
awile ! It seems to run really
good but when iam driving it
say on the highway and go to
punch it,it ack's like it takes a
deep breath before it kick's in
and then it takes of like crazy,
but when it goes to shift up
after that it don't seem like
it's licking in to say second or
drive or overdrive as fast as it
should! I have a not her one
that just flat out goes like
crazy great from start to
finish without any problem at
all! Someone told me that it
might be something to do
with a spring and piston in it
that break and there is some
update you have to do to
some of these transmission's
and also drilling a hole in
there to! Also I dont seem to
get as good enough gas
millage as I did in the other
one I got that has front end
damage to it now! Also does
the ecm have anything to do
with the transmission too!
Pleas help any and all would
be great! Thank you George
from st Louis