The Presenting Symptom ..
once warmed up ( takes about 8 minutes ) there is almost no throttle
repsonse from idle,
but if I shut it off and start it back up ..it's fine for a few minutes.

I can even turn the key off in gear when  when it does it, and it'll be
fine for a few minutes.

If I'm working on it back by the engine and it does this 'no throttle
repsonse thing' and I just hold wide open throttle .....it runs very
rich and may eventually clear out.
Shutting it off and restarting fixes it every time, until it does it again.

the Subject with this system is ..
86 Vangaon with brand new rebuilt auto trans ..rebuilt by German
Transaxle of Bend , oregon. I don't think the trans has anything to do
with it.
it starts and runs cold just fine.
The lopng block  happens to be a 1.9 rebuilt engine with new reground
camshaft and new lifters.
Great compression, no intake leaks, starts nicely, idles just fine ,
goes farily well ...just has this one issue....once warm it just won't
repsond to throttle until I turn off ignition and restart.

have done the following ..
tried several ECU's.
ran two different distributors.
tied two different known good Air Flow Meters, with and without adapter
harness.
Checked carefully that throttle switch is making contact at idle and WOT
..tested that clear to the ECU pins in the main harness.
igniton timing is correct.
compression is good. No intake leaks.
installed a new Temp Sensor II.
checked for shorted oxygen sensor wire.
ran with and without oxygens sensor connected.
Don't think it has anything to do with Idle Air Valve or control unit
for it.

I know it's not a clogged or restircted cat as I put a hollow one on for
testing.
Muffler is decent quality brand and new.

I'm about to install and try out  another Main EFI  harness .

  Grounds ..I believe those are all ok as it's a fresh install and I
generally fuss over every little thing I come across that needs
attention, cleaning, tightening etc.

I almost never put anything together without 'something' on every
threaded fastner, electrical connection etc.

so ..other than trying another 2.1 Digifant EFI which I have ..
I am open to suggestions.

thanks !
Scott