i had the stalling prob,,,,, really it could be over 20 different reasons that i have come across so far from other peoples experience but clean the throttle body, IAC, AFM (air fuel meter), changed spark plugs to ngk platniums and make sure you try to use 95 octane or higher, i find my car splatters abit on 95 so for an extra 4cents/liter i put 98 octane only..... the bov can make it stall but but 9 times out of 10 it has nothing to do with the bov at all...... its way more likely to be the things i said and alot cheaper to do than changing a bov..... so do the easier cheaper things first and if it doesnt work then start the more expensive solutions..... also make sure the idle isnt too low, nissan recomends on a standard r33 off memory 600-700ish rpm.... it says it under the bonnet in one of those stickers if your car still has it