[MA70-3.0GT]

No worries, I was under the impression from that write-up that fuel cut primarily based on the frequency of the signal from the kvafm (partly why the lexus body was used, with the adjustable "bypass" to allow more air to be flowed than the ECU believed), and the ECU then used the O2sensor to correct the resulting lean mixture using the fuel trim.
Then the 550cc injectors were required to "correct" the fuel trim back to the basic level by flowing more fuel for a given pulse width hence leaving more room to correct when boost increases.

All that worried me about the f-con was that modifying further the kvafm signal might affect fuel cut, but you're right it'd still cut at around 80-85% injector duty cycle so no probs.

I was thinking of building a fuel trim monitor using the Vf terminal in the diag. socket, that'd be nice to know what it's doing through the rev range (guess it'd help you pick up a slow switching O2 sensor too)

Anyway, not wishing to hijack the thread sorry ochowdero. so I'll do a bit more research & any questions I'll be sure to bore you with them cre