[s-cars] Missing once more

[Tom Green]

DTCs??   Are you dropping any codes with this problem, Bob ?
With intermittent codes, you may have to read them before too
many shutdowns and restarts or they may disappear, but if it is
low fuel pressure, I would expect a whole bunch of codes for
emissions not in the controllable range, and perhaps the same
with any boost leak.   The coils and PSO's, as we know, may fail
without any such notice.

I'm only about 300 miles "as the crow flies"  but it doesn't sound
like the wonderwagen is flying right now and it's maybe 500 miles
by usable roads.

Tom '95 S6 in Knoxville


> Bob Myers wrote:
> This is driving me nuts.  Yeah, I know - short trip.  :-(
>
> Miss Piggy (RS2ed '95 urS6) has developed another miss.  I have  
> experienced
> several failed PSOs and coils.  This miss appears to be neither.   
> It feels
> almost like some sort of a flutter.  The change in (Stromung)  
> exhaust note
> is significant.  "Brap-rap-rap-rap-rap-rap-rap...".  The "miss"  
> shows up
> only when boost levels exceed 18 psig.  The engine runs perfectly  
> until
> boost hits 18 psig.
>
> This morning I ran a couple of errands and on the first jaunt the miss
> somehow seemed to heal itself without any apparent cause.  (I hate  
> it when
> that happens.)  After shutting the engine down and taking care of some
> brief business I fired Miss Piggy up again and the miss is back.   
> So much
> for the miracle cure.  :-(
>
> "Repairs" done:
> 1.    replaced plugs and boots (it was about time for that anyway).
>
>
> Diagnostics performed:
> 1.    attempted to localize miss to one cylinder - failed.  There  
> seems to be
> no difference between coils and behavior when injectors are  
> disabled one at
> a time.
> 2.    spark intensities appear to be consistent from one cylinder  
> to another.
> 3.    swapped in a known good ECU - no change.
> 4.    swapped in newly burnt chips - no change (either expected or  
> observed).
> 5.    Swapped BPV with another BPV.  No change.
>
> Suggestions anyone?
>
> Bob