Erratic Manifold Pressure: Please help

["Renier Meyer" <RMeyer.rdi@reutech.co.za>]

I have problem creeping up on me again. (89 200T)

Whenever I boost higher than 1.5 bar, the analog boost gauge goes 
crazy. It oscillates between 0.1 - 0.2 bar higher and lower than the current 
reading.

If the car is slowly accelerated, it sometimes happens from 1.2bar.
The car goes well, but obviously looses power when this happens.

The head has been redone about four months ago for the second time 
, where they found a valve sleeve that was loose on No1 cylinder.  
The symptoms was an occasional puff of smoke so bad that you could 
not see the traffic behind you. 

The first time the head was done, they replaced bent valves.
These bent  after loosing a timing belt when the waterpump 
bearings seized.

The car was done by a reputable firm, under supervision of the local 
Audi agent. All bits that were worn got replaced, and they checked 
the motor very carefully (or so they say).

I can see the same symptoms as before the oil started getting blown 
out. For the first three months the pressures were fine, and the car 
really pulled well.

Questions:

Is there any way that I could have caused this, say by running higher 
boost than normal? (The higher boost was first done by a vacuum pipe 
mod to the WGFV, and now with a carefully tested remapped ECU eprom).

The car is driven up a steep hill just after start-up. Could the oil 
drain away from No1 cylinder be causing this?

Is there any test that I can carry out without stripping the head?

Any way to fix this? The job is still under guarantee for the next 
seven months, but I would like to get to the bottom of this and have 
it sorted out once and for all.

The detail mechanical side on this issue is a bit beyond me at this 
stage.

HELP OR SUGGESTIONS DESPERATELY NEEDED, private or on the net 
is fine.

TIA

Renier Meyer
89 200T Durban South Africa.