[V6-12v] all quiet on the AUDI Front

[James4ihl at aol.com]

Well,

Since we've been asked for problems since its 'too quiet' out there... get 
your teeth into this one guys:

Yep, you guessed it. Its the old hesitation problem again!!!

Here's what's changed since I last asked your collective wisdom about the 
problem:

1. Car was taken to Audi shop and hooked up to diagnostic computer. No faults 
stored in permanent memory.
2. Audi tech told me they had found nothing except (sic.) an 'intermittent 
non-signal from one lambda (O2) sensor. I said - "Well, don't you think the 
cause of my intermittent hesitation could be an intermittent non-signal?" "Well, 
maybe," he said, "but we usually replace the Coolant Temp Sender first because 
they're usually the only thing that can go without leaving a permanent fault 
code."
3. So I replaced the coolant temp sender today. Result? Still hesitates. Oh, 
and now I have a noisy hydraulic lifter too, despite the procedure going 
nowhere near the rocker covers :)

If I don't diagnose this soon, I'm gonna go nuts, I swear!! So, please, any 
good ideas? Could you:

1. Think of anything that could be causing this, electrical, or mechanical.
2. Think about this: when the hesitation occurs, its generally on 
accelleration. If you try to 'accellerate through' the hesitation (i.e. pressing harder 
on the throttle) the car will stay at the same revs for as long as it decides 
to, then suddenly jump to correct revs for that throttle position. If, on the 
other hand, you back off the throttle a little way when it hesitates, it will 
'clear' (for want of a better term and let you accellerate smoothly again. Now 
what could cause that?
3. Tell me how to do the following:
a) if my manual tells me to 'check for an open circuit between connector X 
and connector Y, what setting do I use on a multimeter? Resistance? Voltage? If 
resistance, what kind of reading would be good and bad for an open circuit?
b) if my manual tells me to check for a short circuit, same question as 
above...
c) if my manual says to check for an earth fault between connector X and 
'engine earth', same question again...
d) does anyone have a procedure, or any warnings, about disconnecting the 
multi-pin connectors to the ECU in order to test the wiring between the 
connectors in the engine bay and the multi-pins in there? Also how does one check the 
continuity - do you need a multi meter with bloody great long leads, or is 
there a way of extending them reliably?

Please help, I'm really fed up with this damn problem now!

Cheers :)
James