Rasta,
See Mark's post #9 above. When the fuel pumps shut down you don't get a sudden lean condition, you get a sudden shut down condition.
You list a 1980 924 Turbo in your signature block, I don't know if you car has the same overboost switch or not. When my switch opened under hard acceleration both of my hands came off the steering wheel, that's how hard the engine kill is. If you have never experienced that, you really cannot understand the function of that switch.
This was the real reason for my overboost situation. There was never any detonation, none. The control pressure line is perfect.
The car is back on the road and running perfectly.
Mark