Help with Evo 2-Engine

My BF recently got his gearbox rebuilt as he blew it along with his clutch so he put the new gears in and it ran sweet until he boosted slightly and it would sound like it was missing e.g thought it was the plugs and leads so got brand new ones and it still does the same thing..its got a link ecu too....but weve tried and tried to figure out what it is without having to spend a lot of money...so if anyone has any ideas as to why it would sound like it was farting please help me out...its our car for new years!!!!

hi IF THE SOUND HAD SHOW SINCE YOU BOOSTED YOUR ENGINE YOU SHOULD FIRST OF ALL CHECK AFR AND ALSO THE MAP LIMIT MAYBE IT IS SET TOO LOW. JASON E MAIL: jaske@global.net.mt

Yeah, most likely the MAP limit being hit due to increased boost.  It could be going really rich or lean if you are running it into areas it hasn't been tuned for.