It is not necessarily caused by running lean. Lots of folks get fuel cut in the midrange (2800-4400 rpm) because the ecu senses that TOO MUCH air is going into the engine for that rpm, load, and throttle position. The ecu intentionally runs the entire powerband rich. But the airflow meter says to the ecu...hey, I have 500 cfm going by me. The ecu says...hey, that's too much air...the bov or the wastgate is stuck and the boost will destroy the motor...lets slow things down a bit...
contact these guys at
http://www.technomotive.com. They are the best dsm ecu gurus around and can explain it way better than i can. BTW, a stock engine can be made to hit fuel cut with free mods.