[s-cars] Missing once more

[Robert Myers]

Hi Y'all,

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