could be an adjustment of the throttle position sensor (TPS) required.
The factory service manual gives the procedure.
On my '94, it was connect an ohm meter to specified terminals, then
insert a thickness gauge of specified thickness and check for
continuity. Also was a reading given for wide open throttle IIRC.
I did all these adjustments when the throttle body was removed to
replace the idle air control valve.
I mention the TPS because that is one main input to your electronically
controlled transmission (for downshifting) - throttle position.
Another thing to check, although this has more influence on upshifting,
would be the cable that runs from the round wheel at the throttle body
to the transmission. Sorry forgot the correct term. It feeds a
mechanical sense to the transmission for throttle position.
On mine, after adjusting the throttle cable, the transmission cable was
OK.
Adjust the throttle cable by checking for wide open throttle.
I did this by placing a short length of 2x4 over the gas pedal inside
the car, and then a large concrete cinder block over the wood to press
the gas pedal fully to the floor.
The under the hood, check to see if there is still "play" or looseness
in the throttle cable. If so, turn the adjustment sleeve at the
throttle body so that the throttle valve is fully open. You should also
make sure there is still some slack in the cable at idle position, but
I had no problem there.
Not sure if these items would be enough to correct your problem, but in
my case both items did require some adjustment, and both seemed to
improve responsiveness of the transmission overall - both downshifting
and upshifting.