ur-q air temp sensor

[harrison@indigo.ie (George Harrison)]

Greetings from Ireland Folks.....

Perhaps someone can assist -
I've a problem with my ur-q which started about six month ago and has slowly
been getting worse. Symptoms are on startup after sitting overnight engine
fires almost immediately (good) but if I press the gas pedal AT ALL it
starts to die. It will remain at idle no problem but don't touch the gas!
After idling for about 4-5 minutes it will then respond to the pedal but
very poor on power and very rough - bad mis-firing which does not seem to be
confined to any one cylinder. This applies throughout the whole rev range
from idle to 6500rpm. Idle very lumpy when warm. So far I have replaced the
fuel pump, both fuel filters, the fuel metering head, spark plugs, plug and
coil wires, coil and have even gone as far as replacing the head gasket,
head skimmed (2 thou), new valve guides, valve seats re-cut, and valve faces
refnished. I threw in a new water pump, timing belt, alternator belt and PAS
belt just for good luck. Even went as far as new studs, nuts, bolts, washers
etc. for every joint that was opened! I have also had the fuel injectors
tested and they are confirmed OK. I used new injector 'o' rings and Bako
inserts when refitting injectors. I've tried a spare brain (MAC01) but no
difference. Turbo comes in when it should, giving the extra boost expected
but still with mis-fire. 
Two things have been suggested to me:
1. Warm-up regulator (fuel pressure regulator)
   With new fuel pump and filters fitted I'm reading 5.2 bar fuel pressure
coming from the fuel tank. If memory serves me right (some time since I
checked) I read 4.2 bar coming from warm-up regulator engine hot or cold.
   Suggestion was the problem lies in the pressure from the reg. being too
high resulting in the flap in air-flow meter not being able to rise when I
press gas pedal....recommended replacing the reg.

2. Air temp sensor (on inlet manifold)
   Suggestion here was that a dodgy sensor can cause poor running throughout
rev    range.(I thought this sensor only had an effect when over 4000rpm).
   I've tested it using the procedure recommended in the Audi Introductory
Service Training Information Manual (many long overdue thanks to Mike    of
Bedford N.H. for sending me this invaluable book). Book says reading at
room temp should be 13 - 33 ohms.....my reading 22ohms. I applied hot air
from hairdryer - reading goes up to 26 ohms. Then I applied hot air from
portable gas soldering iron (temp approx 300c) - reading only goes up to 32
ohms. Still less than the book said for room temp! Can this be right?
   Does anyone know what reading I should be getting?

Can anyone provide any hints on this problem? Mighty p%^&*d off at this
stage and 880 Pounds (1200USD) out of pocket without solving problem. Wife
says either car goes or I go! Help!

TIA,
George Harrison,
Co. Kildare,
Ireland.

'85 ur-quattro
'86 80 Sport