Well, in spite of all the helpful advice from all you good folks, we still
got us a nasty problem.  A potted history:
Around three months ago started having signs of a problem or four.  Coolant
going somewhere. Checked it out, had head seals changed on driver side.
Then fuel consumption jumped from 27 mpg to 14 mpg.  Advised to change the
O2 sensor.  Changed it and consumption went back down for a for a few weeks.

Then engine began surging.  It felt like ( and still does ) an afterburner
or supercharger  cutting in and out.  One could feel the kick.  Checked all
the obvious things listed in Bently.  Westy took to going down the road
trailing huge clouds of black smoke.  Obviously  running too rich.
Confirmed by mileage which dropped back to 10 mpg.  Took it to a mechanic I
know from previous experience is good.  But - he doesn't profess to be an
expert on VW.  He Diagnosed a bad ECU. I replaced the ECU with one known to
be good.  No improvement

More advice from you folks.  Read archives on the  air flow meter spring
setting. Then on April 13 (bad choice  you say!)  I  worked the ~@#$%^&*
thing over. 
1 Checked throttle position switches cold - within specs
2 Pulled O2 sensor. Filthy. Cleaned with Brakleen and electrical contact
cleaner and tooth brush
3 Checked system from multi-pin connector
-  air intake potentiometer is 1K not 560 ohms
-  Temp sensors both at 4000 ohms with air temp at 10-15 (don't have a
thermometer for that check)
-  Air intake sensor check - ohms change when it moves but very little
-  Air flow meter wipe survace cleaned and contacts bent back to create new
arc    surface
4 Injectors seemed OK but  passenger rear leaked a bit.  (what the blazes is
the   cylinder numbering on those engines.  Even Bently can't figure it out)
5 Ecu well grounded to engine and frame.
6 Tightened AFM spring one notch at a time till engine quit smoking at idle.
Up   six notches.

 Test drive - engine: black smoke ; driver: blue smoke.  Rest period to
recover from heart attack.

April 17.  Replace suspect fuel injector but tested before replacing and -
passenger rear didn't leak but passenger front didn't spray the way it did
the first two tests.  Thats the one I replaced.

Today,  replaced  temp. sensor II.  Test drive:  I have a vacuum gauge
mounted on the dash and at 15 to 20 inches seems OK  on flat and level
except cutting in and out of some electrical /electronic  controller.  Can
be felt.  As soon as the engine loads down either from accelerating  or
going up a hill,  when the vacuum drops to near 5" ,  clouds of black smoke.
Tried  tightening the
AFM up 12 notches but engine ran rough so backed it off.

Aside from jacking up the engine cover and driving a Jetta under it, is
there  any  hope  for this monster.

Earl from Sunny Sooke