[s-cars] Going insane... UrS4 falling on it's face at WOT

[Wayne Dohnal]

I'm chasing a similar problem on my stock '94.   The behavior is clearly 
visible on the boost gauge:  After I run at full boost (~15 psi) for a 
second or two, the ecu cuts the engine off.  If I hold the pedal down, the 
car bucks like crazy between full power and fully cut off.  Once I cause 
this situation, the engine cutoff occurs at 5 PSI until I do an engine 
shutdown and restart.  Then the cutoff point goes back to 15 PSI.    I've 
improved the situation some by fixing a loose hose on the moisture trap 
under the plastic cover by the firewall.    I'm getting a code 2413 "mixture 
adjustment".  The MIL light isn't on, which the Bentley says it is with a 
2413 code.

I've given the MAF sensor a good cleaning and I'm going to try replacing my 
never-replaced bypass valve.  Have you replaced yours?  I didn't see it on 
the list of new parts.  Other suggestions appreciated.   The Bently lists a 
lot of possible causes for the 2413 code  Is there any particular thing 
that's usually behind it?

Wayne
1994 S4