Throttle Response Problems

[ABTSZ]

Hi all,

I acquired a fuel-injection sytem from an '88 Chevy Berreta 2.8 V6 (730 MAP
based system), and I put it on my Jag 4.2 straight six, using a manifold and
throttlebody from a later fuel injected Jag.  The injectors are 24# Ford SVO
(the original jag injectors were 20# low impedence, and not large enough for
my modified engine.)
I eliminated everything from the harness except the MAP, TPS, water temp, air
temp, knock sensor, and DIS.  I have the P\N wire grounded.
The car runs pretty well, EXCEPT for the throttle response.  The throttle
response is so bad, that from a stop, the car will stall when I step on the
gas unless I press the gas pedal as softly and slowly as I possibly can.  Even
then the car stumbles rather severely before taking off.  The throttle
response is pretty poor, even at speeds up to about 60 MPH.   The car
accelerates smoothly once it gets going.  Idle is pretty good, too.  WOT is a
little rich, but thats not too bad, actually!  
I have checked out the TPS, since I would imagine this is where the problem
would originate, but everything seems to be OK.  I get no error codes, and I
have the TPS set to about .65 volts at idle (the manual states .45 to .85 V at
closed throttle) and it goes up to about 4.5v at full throttle.  I have tried
adjusting TPS in different positions, all the way up to 1.1V at idle, with the
best results at higher voltages, but still unacceptable throttle response.
The only thing I can think of is that the Jag throttle plate is SO MUCH larger
than the Chevy (about 65mm vs. @ 45mm? (I didn't measure, but its a BIG
difference.))  I think this might result in a much larger amount of air
rushing in at small throttle openings.  But then the engine is much larger,
also.  So ratios might be the same, and that is what counts.
Has anybody else had similar problems?  Does anybody have any ideas as to what
could be causing this or any suggestions or work arounds?
ANY suggestions would be welcome. This seems to be the only (however severe)
problem with this system so far.  I have excellent idle, acceleration, milage,
etc.  But the throttle response problem makes the car almost un-drivable in
traffic (and maybe even a little dangerous!)

TIA,
Adam

PS I even checked the Harness for continuity, and there are no problems there.