Ok so I just recently got my hands on a KA24DET S13 and to be honest i know nothing about turbos. So hears the deal when I'm driving it, it runs fine the A/F Gauge jumps around a bit but nothing to drastic but then when i let off the gas at around 3k+ the Gauge will read --- and the car will die out. I know its a air fuel problem but can't seem to figure where to start looking. The guy i got it from told me its cause the reserc BOV was too close to the turbo and it was to be an easy fix but i don't feel that its the problem.

Some pics and info on the setup may help.

Would need to see if the IACV is hooked up as well.

When the air fuel gauge reads --- or XXX it's because the air fuel levels gave exceeded the limits of the sensor. When the BOV vents to the atmosphere it creates a overly rich condition which causes stalling.

Try disconnecting the BOV and see if the problem goes away.

It might also be your tune.
The same way it's important to have a good afr when accelerating and getting into boost, it's the same for deceleration.