[s-cars] Need Diagnostic Help

[Bob Rossato]

Hello fellow S-heads,

A friend of mine is having some intermittent cutoff problems on his S4.
It happens during wide open throttle.  He states that it is not like a
misfire, it's more like a hard cutoff such as hitting the rev limiter,
though he's nowhere near the rev limit.  Has happened a handful of times
over the last few weeks.  When it's not acting up it pulls strongly, so
I wouldn't suspect the usual ECU boost line coming off as it wouldn't
reseal it self.  And besides, he's adamant that it's not just a loss of
boost, it's a complete loss of power.  Again, only during WOT.  Ease off
on the throttle and the engine comes back.  I also wouldn't suspect the
POS or coils as I would expect that to be more of a misfire, not a
complete loss of power.  

We checked the codes today and got the following 3 codes:

00519 - Intake Manifold Pressure Sensor (G71)
            06-10 - Signal to High - Intermittent
00561 - Mixture Adaptation
            14-00 - Adaptation Limit (Add) Exceeded
00544 - Maximum Boost Pressure Exceeded
            27-10 - Implausible Signal - Intermittent

The 00561 mixture adaptation I've seen before on my car and others but
I've never noticed anything wrong performance wise so I don't think
that's the first thing I'd chase down.  The 00519 & 00544 are more
relevant I think.  Is this an indication of a problem with the WGFV?  We
will be checking the line to the ECU and water trap, as well as boost
hoses anyway just to make sure.  Any other thoughts? 

The car is a '94 S4 with ~53k miles.  Completely stock.  And let's see,
what else... oh yeah, it's Pearl White if that helps.

Bob