Does anyone know if Air is metered before it enters the engine in the GTR like a conventional MAF or metered in the engine like a MAP sensor would pick up.
If air is measured before it enters the engine then it wont be able to account for the air that's vented out of the BOV and not recirculated, hence running a little rich and possibly rough idle.
It was the same for UK Supras VS Jap, UK's had MAF and Jap had Map sensor, Jap's were fine with BOV but UK ones didn't run well on them.
Donbona - I suspect yours is fine as your not completely venting to atmosphere judging by what you said.