Fuel cut is all in the ECU. Are you running a stock chip? What other mods? You need to get a chip from Keydiver, or some other engine management correction to get rid of fuel cut.
Just so you have an understanding, Fuel cut is a set threshold in the ecu, ie. if X amount of air is reached, don't open injectors. When you throw on a bigger turbo or exhaust/intercooler, you can flow more air through the MAF and that threshold is easier to reach. Keydiver can reprogram your eprom so that either the ECU no longer checks airflow, or the threshold is raised up to allow for more air.
The problem with not venting your BOV with an otherwise stock setup is that the MAF (which is reading the amount of air going to the engine) is before the BOV. This means that when you let off the gas, and the BOV vents to the atmosphere, the ecu is adding the correct amount of fuel that it thinks it needs to based on the amount of air coming through the MAF. If your air metering device is AFTER the BOV, any vented air isn't already compensated for.
Hope that makes sense /ubbthreads/images/graemlins/crazy.gif
